Filtered cathodic arc deposition method and apparatus

ABSTRACT

An apparatus for the application of coatings in a vacuum comprising a plasma duct surrounded by a magnetic deflecting system communicating with a first plasma source and a coating chamber in which a substrate holder is arranged off of an optical axis of the plasma source, has at least one deflecting electrode mounted on one or more walls of the plasma duct. In one embodiment an isolated repelling or repelling electrode is positioned in the plasma duct downstream of the deflecting electrode where the tangential component of a deflecting magnetic field is strongest, connected to the positive pole of a current source which allows the isolated electrode current to be varied independently and increased above the level of the anode current. The deflecting electrode may serve as a getter pump to improve pumping efficiency and divert metal ions from the plasma flow. In a further embodiment a second arc source is activated to coat the substrates while a first arc source is activated, and the magnetic deflecting system for the first arc source is deactivated to confine plasma to the cathode chamber but permit electrons to flow into the coating chamber for plasma immersed treatment of the substrates. A load lock shutter may be provided between the plasma duct and the coating chamber further confine the plasma from the first arc source.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit under all relevantU.S. statutes, including 35 U.S.C. 120, to U.S. application Ser. No.09/826,940 filed Apr. 6, 2001, titled FILTERED CATHODIC ARC DEPOSITIONMETHOD AND APPARATUS, which in turn claims priority under 35 U.S.C. 119to Canadian Appl. No. 2,305,938 filed Apr. 10, 2000.

FIELD OF THE INVENTION

[0002] This invention relates to the application of coatings in a vacuumapparatus. In particular, this invention relates to an apparatus whichgenerates a plasma of electrically conducting materials for theapplication of coatings to surfaces of a substrate by way ofcondensation of plasma. The apparatus can be used in mechanicalengineering, instrument and tool making, in the production of electronicequipment, and in other fields of industry.

BACKGROUND OF THE INVENTION

[0003] Many types of vacuum arc coating apparatus utilize a cathodic arcsource, in which an electric arc is formed between an anode and acathode plate in a vacuum chamber. The arc generates a cathode spot on atarget surface of the cathode, which evaporates the cathode materialinto the chamber. The cathodic evaporate disperses as a plasma withinthe chamber, and upon contact with the exposed surfaces of one or moresubstrates coats the substrates with the cathode material, which may bemetal, ceramic, etc. An example of such an arc coating apparatus isdescribed in U.S. Pat. No. 3,793,179 issued Feb. 19, 1974 to Sablev,which is incorporated herein by reference.

[0004] An undesirable result of the vacuum arc coating technique is thecreation of macroparticles, which are formed from molten cathodematerial vaporized by the arc. These macroparticles are ejected from thesurface of the cathode material, and can contaminate the coating as itis deposited on the substrate. The resulting coating may be pitted orirregular, which at best presents an aesthetic disadvantage, but isparticularly problematic in the case of coatings on precisioninstruments.

[0005] In order to reduce the incidence of macroparticles contacting thesubstrate, conventionally a vacuum arc coating apparatus may beconstructed with a filtering mechanism that uses electromagnetic fieldswhich direct or deflect the plasma stream. Because macroparticles areneutral, they are not influenced by these electromagnetic fields. Suchan apparatus can therefore provide a plasma duct between the cathodechamber and a coating chamber, wherein the substrate holder is installedoff of the optical axis of the plasma source. Focusing and deflectingelectromagnets around the apparatus thus direct the plasma streamtowards the substrate, while the macroparticles, uninfluenced by theelectromagnets, would continue to travel in a straight line from thecathode. An example of such an apparatus is described and illustrated inU.S. Pat. No. 5,435,900 issued Jul. 25, 1995 to Gorokhovsky for an“Apparatus for Application of Coatings in Vacuum”, which is incorporatedherein by reference.

[0006] Another such apparatus is described in the article “Properties ofTetrahedral Amorphous Carbon Prepared by Vacuum Arc Deposition”, Diamondand Related Materials published in the United States by D. R. McKenziein 1991 (pages 51 through 59). This apparatus consists of a plasma ductmade as a quarter section of a tore surrounded by a magnetic system thatdirects the plasma stream. The plasma duct communicates with twochambers, one chamber which accommodates a plasma source and a coatingchamber which accommodates a substrate holder.

[0007] The configuration of this apparatus limits the dimensions of thesubstrate to be coated to 200 mm, which significantly limits the rangeof its application. Furthermore, there is no provision in thetore-shaped plasma duct for changing the configuration of the magneticfield, other than the magnetic field intensity. Empirically, in such anapparatus the maximum value of the ionic current at the exit of theplasma duct cannot exceed 1 percent of the arc current. This is relatedto the turbulence of the plasma stream in the tore, which causes adrastic rise in the diffusion losses of ions on the tore walls.

[0008] The apparatus taught by Gorokhovsky in U.S. Pat. No. 5,435,900incorporates a plasma duct surrounded by the deflecting magnetic system,a plasma source and a substrate holder mounted in the coating chamberoff of the optical axis of the plasma source, where the plasma sourceand the substrate holder are surrounded by the focusing electromagnets.The plasma duct is designed in the form of a parallelepiped with thesubstrate holder and the plasma source mounted on adjacent planes. Themagnetic system that forces the plasma stream towards the substrateconsists of linear conductors arranged along the edges of theparallelepiped. The plasma duct has plates with diaphragm filtersconnected to the positive pole of the current source and mounted on oneor more planes (not occupied by the plasma source) of the plasma duct.These plates serve as deflecting electrodes to establish an electricfield in a transversal direction relative to the magnetic field lines,to guide plasma flow toward the substrate to be coated.

[0009] The advantages provided by U.S. Pat. No. 5,435,900 to Gorokhovskyinclude increasing the range of dimensions of articles (substrates)which can be coated, and providing the user with the option of changingthe configuration of the magnetic field in order to increase ioniccurrent at the exit of the plasma duct to 2 to 3 percent of the arccurrent.

[0010] A deflecting electrode is also described in U.S. Pat. No.5,840,163 issued Nov. 24, 1998 to Welty, which is incorporated herein byreference. This patent teaches a rectangular vacuum arc plasma sourceand associated apparatus in which a deflecting electrode is mountedinside the plasma duct and either electrically floating or biasedpositively with respect to the anode. However, this device requires asensor, which switches the polarity of the magnetic field when the arcspot on the rectangular source has reached the end of the cathode, inorder to move the arc spot to the other side of the cathode. Thisresults in an undesirable period where the magnetic field is zero; thearc is therefore not continuous, and is not controlled during thisperiod. This ‘pseudo-random’ steering method cannot consistently producereliable or reproducible coatings.

[0011] If the potential of the deflecting electrode (V_(d)) locatedopposite the plasma source is greater than the potential of the plasmasource wall (V_(w)), an electric field occurs between them. Theintensity of the electric field is given by: $\begin{matrix}{E \propto \frac{V_{d} - V_{w}}{d} \propto {{\sigma \left\lbrack {1 + \left( {\omega_{e}\tau_{e}} \right)^{2}} \right\rbrack}I_{d}}} & (1)\end{matrix}$

[0012] where

[0013] d is the distance between the plate and the plasma duct wall,

[0014] ω_(e) is the gyro frequency of magnetized plasma electrons,

[0015] τ_(e) is the characteristic time between electron collisions,

[0016] σ is the specific resistivity of the plasma in the absence of amagnetic field, and

[0017] I_(d) is the current of the deflecting electrode.

[0018] Because ω_(e) is proportional to the plasma-guiding magneticfield B, (i.e. ω_(e) ∝ B), the transversal electric field E_(t) asdetermined by formula (1) will be proportional to B², as shown by thefollowing equation:

E_(t)∝σ[1+(ω_(e)τ_(e))²]I_(d)∝B_(t) ²I_(d)  (²)

[0019] where B_(t) is the component of the magnetic field which istangential to the surface of the deflecting electrode.

[0020] An ion is influenced by the force:

F _(i) ∝Q _(i) ×E _(i)  (3)

[0021] where Q_(i) is the ion charge. Combining formulae (2) and (3)yields:

F_(i)∝Q_(i)B_(t) ²I_(d)  (⁴)

[0022] This force causes the ion to turn away from the wall opposite theplasma source and directs it towards the substrate to be coated.

[0023] In the prior art, most of the surface of the deflecting electrodeis disposed in a position where the transversal component of themagnetic field is strong and the tangential component of the magneticfield is relatively weak, which results in low magnetic insulation alongthe deflecting electrode. This is a disadvantage of the systems taughtby Gorokhovsky and Welty, as it results in a weak deflecting electricfield which is not strong enough to change the trajectory of heavy metalions, such as Gf⁺ and W⁺, toward the substrate to be coated. Even in thecase lighter ions such as Al⁺ and Ti⁺ the degree of ion deflection isslight, which results in substantial losses of metal ions before theplasma reaches the position of the substrate(s).

[0024] Another method used to reduce the incidence of macroparticlesreaching the substrate is a mechanical filter consisting of a baffle, orset of baffles, interposed between the plasma source and the plasma ductand/or between the plasma duct and the substrate. Filters taught by theprior art consist of simple stationary baffles of fixed dimension, suchas is described in U.S. Pat. No. 5,279,723 issued Jan. 18, 1994 toFalabella et al., which is incorporated herein by reference. Suchfilters create large plasma losses and a very low plasma yield, becausethe baffles destroy the geometry of the plasma duct.

[0025] Other mechanical filtering mechanisms, such as that taught byU.S. Pat. No. 5,435,900 to Gorokhovsky, trap macroparticles by alteringthe path of the plasma stream off of the optical axis of the plasmasource toward the substrate, and trapping macroparticles in a baffledisposed generally along the optical axis of the cathode. However, thissolution affects macroparticles only and does not allow for control ofthe plasma composition in the coating chamber, for example where itwould be desirable to expose the substrate(s) to an ionized plasmawithout a metal component, as in plasma immersed processes such as ionimplantation, ion cleaning, ion nitriding and the like. As such, priorart vacuum coating apparatus is suitable for use only in plasma vapordeposition (PVD) processes and a separate apparatus is required forplasma immersed processes.

SUMMARY OF THE INVENTION

[0026] The invention overcomes these disadvantages by providingmechanisms for the effective deflection of the plasma flow, and forcontrolling the composition of the plasma to allow the apparatus to beused for arc processes other than PVD coating.

[0027] In one embodiment the invention provides a coating chamberdisposed off of the optical axis of a filtered arc source containing acathode, wherein an isolated repelling electrode is positioned in theplasma duct, separate from the deflecting electrode, such that thedeflecting magnetic field is substantially tangential to a substantialportion of the surface of the repelling electrode. The current appliedto the isolated repelling electrode can be varied independently of thecurrent applied to the deflecting electrode, thus allowing the electricfield about the repelling electrode to be enhanced and facilitating thefunction of sustaining the arc in the plasma duct, without altering thedeflecting properties of the deflecting electrode

[0028] In a further embodiment the repelling electrode is disposedwithin the plasma duct in the path of the plasma stream, the placementand orientation of the repelling electrode thereby creating an electricfield which divides the electric current, physically dividing the plasmastream, which merges after passing around the repelling electrode. Theinvention thus reduces the loss of metal ions at the substrate in avacuum arc coating apparatus, and improves the quality of the vacuumwithin the apparatus. The dividing electrode, being electricallyisolated and independently energized, further serves as an auxiliaryanode for sustaining the arc in the plasma duct. This embodiment of theinvention is particularly advantageously implemented in a vacuum arccoating apparatus in which two plasma sources disposed on opposite sidesof a common plasma duct each generate a plasma stream which combine atthe entrance to the plasma duct and flow into the coating chamber.

[0029] The repelling electrode and/or the deflecting electrode can bemaintained at floating potential, or can be connected to the positivepoles of separate power sources so that the applied current can bevaried independently of one another.

[0030] In a further embodiment the deflecting electrode is surrounded bya baffle for removing macroparticles from the plasma stream, which alsoserves as a getter pump to remove gaseous contaminants from within theapparatus. When the baffle is maintained at floating or negativepotential, ions are adsorbed to the surface of the baffle.

[0031] The invention also provides a multiple-cathode apparatus suitablefor use in plasma-immersed processes as ion implantation, ion nitriding,ion cleaning and the like. In these embodiments a first filtered arcsource containing one or more cathodes generates cathodic evaporate forcoating the substrate, while the deflecting and focusing magnetic fieldsaffecting a second filtered arc source are deactivated so that cathodicevaporate does not flow toward the substrates. The second filtered arcsource thus functions as a powerful electron emitter for plasma immersedtreatment of the subtrates.

[0032] Optionally in these embodiments a load lock shutter comprising ametallic grid is disposed between the plasma duct and the coatingchamber, to control communication between the plasma source and thecoating chamber. Where particularly contaminant-free conditions arerequired the load lock shutter can be closed to contain macroparticlesand metal vapour within the cathode chamber(s) and plasma duct, butpermit the passage of electrons into the coating chamber to thusincrease the ionization level of a gaseous component within the coatingchamber. The load lock shutter can be charged with a negative potential,to thus serve as an electron accelerator and ion extractor. Optionallyload lock shutters may also be provided between the filtered arc sourceand the plasma duct, and/or between the cathodes and the delectingelectrode within a filtered arc source.

[0033] The load lock shutters can also be used in conjunction with thedeflecting electrode operating as a getter pump, to improve the qualityof the vacuum in the chamber.

[0034] The present invention thus provides an apparatus for theapplication of coatings in a vacuum, comprising at least one filteredarc source comprising at least one cathode contained within a cathodechamber, at least one anode associated with the cathode for generatingan arc discharge, a plasma duct in communication with the cathodechamber and with a coating chamber containing a substrate holder formounting at least one substrate to be coated, the substrate holder beingpositioned off of an optical axis of the cathode, at least onedeflecting conductor disposed adjacent to the plasma source and theplasma duct, for deflecting a plasma flow from the arc source into theplasma duct, and at least one metal vapor or sputter deposition plasmasource disposed in or near a path of the plasma flow, comprising amaterial to be evaporated.

[0035] The present invention further provides an apparatus for theapplication of coatings in a vacuum, comprising at least one filteredarc source comprising at least one cathode contained within a cathodechamber, at least one anode associated with the cathode for generatingan arc discharge, a plasma duct in communication with the cathodechamber and with a coating chamber containing a substrate holder formounting at least one substrate to be coated, the substrate holder beingpositioned off of an optical axis of the cathode, at least onedeflecting conductor disposed adjacent to the plasma source and theplasma duct, for deflecting a plasma flow from the arc source into theplasma duct, at least one metal vapor or sputter deposition plasmasource in communication with the plasma duct, the metal vapor or sputterdeposition plasma source being positioned off of an optical axis of thecathode, and at least one deflecting conductor disposed adjacent to themetal vapor plasma source and the plasma duct, for deflecting a plasmaflow from the metal vapor plasma source into the plasma duct.

[0036] The present invention further provides a method of coating anarticle in a coating apparatus comprising at least one filtered arcsource comprising at least one cathode contained within a cathodechamber, at least one anode associated with the cathode for generatingan arc discharge, a plasma duct in communication with the cathodechamber and with a coating chamber containing a substrate holder formounting at least one substrate to be coated, the substrate holder beingpositioned off of an optical axis of the cathode, at least onedeflecting conductor disposed adjacent to the plasma source and theplasma duct, for deflecting a plasma flow from the arc source into theplasma duct, and at least one metal vapor or sputter deposition plasmasource in communication with the plasma duct, the method comprising thesteps of: a. generating an arc between the cathodic arc source and theanode to create a plasma of cathodic evaporate, b. evaporating amaterial in the metal vapor or sputter deposition plasma source togenerate a metal vapour or sputter flux in the vicinity of the metalvapor plasma source, and c. deflecting a flow of the plasma toward thesubstrate holder, whereby the flow of plasma mixes with the metal vapouror sputter flux prior to coating the at least one substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In drawings which illustrate by way of example only preferredembodiments of the invention,

[0038]FIG. 1 is a schematic plan view of a prior art vacuum arc coatingapparatus,

[0039]FIG. 2 is a schematic plan view of a single source vacuum arccoating apparatus embodying the invention,

[0040]FIG. 3a is a schematic plan view of a dual-cathode filtered arcsource vacuum arc coating apparatus embodying the invention,

[0041]FIG. 3b is a schematic plan view of a double-channel dual-cathodefiltered arc source vacuum arc coating apparatus embodying theinvention,

[0042]FIG. 4 is a top plan view of a further embodiment of the vacuumarc coating apparatus of FIG. 3 providing a plurality of cathode pairs,

[0043]FIG. 5a is a side elevation of the arc coating apparatus of FIG.4,

[0044]FIG. 5b is a cross-sectional side elevation of a furtherembodiment of the arc coating apparatus of FIG. 4 having impulsecathodic arc sources,

[0045]FIG. 5c is a schematic plan view of a dual-cathode filtered arcsource vacuum arc coating apparatus of FIG. 4 having impulse laserigniters,

[0046]FIG. 6 is a front elevation of the dual-cathode filtered arccoating apparatus of FIG. 4,

[0047]FIG. 7 is a cross-sectional view of a cathode pair in thedual-cathode filtered arc coating apparatus of FIG. 4,

[0048]FIG. 8a is a schematic plan view of a dual filtered cathodicvacuum arc coating apparatus providing auxiliary anodes within thecoating chamber,

[0049]FIG. 8b is a schematic plan view of a dual filtered cathode vacuumarc coating apparatus providing magnetron-arc sources within the coatingchamber surrounded by an auxiliary arc anode,

[0050]FIG. 8c is a schematic plan view of a further embodiment of a dualfiltered cathode vacuum arc coating apparatus providing magnetron arcsources within the coating chamber surrounded by an auxiliary arc anode,

[0051]FIG. 8d is a schematic plan view of a dual filtered cathodicvacuum arc apparatus providing a resistive evaporation hot anode (REHA)arc plasma within the coating chamber,

[0052]FIG. 8e is a schematic plan view of a dual filtered cathodicvacuum arc apparatus providing a resistive evaporation hot anode (REHA)arc plasma within the plasma duct,

[0053]FIG. 8f is a schematic plan view of a dual filtered cathodicvacuum arc apparatus providing an electron beam evaporation hot anode(EBEHA) arc source within the plasma duct,

[0054]FIG. 8g is a schematic plan view of a dual filtered cathodicvacuum arc apparatus providing an electron beam evaporation hot cathode(EBEHA) arc source within the plasma duct,

[0055]FIG. 8h is a schematic plan view of a further embodiment of a dualfiltered cathodic vacuum arc coating apparatus providing a resistiveevaporation hot anode (REHA) arc plasma source within the plasma duct,

[0056]FIG. 8i is a schematic plan view of a further embodiment of a dualfiltered cathodic vacuum arc coating apparatus providing a resistiveevaporation hot anode (REHA) arc plasma source within the coatingchamber,

[0057]FIG. 8k is a schematic plan view of a filtered arc plasma sourceion deposition (FAPSID) surface engineering system utilizing differentmetal vapor deposition sources in filtered arc plasma immersionenvironment,

[0058]FIG. 8l is a schematic side view of the FAPSID surface engineeringsystem of FIG. 8k,

[0059]FIG. 8m is a schematic plan view of a dual filtered cathodicvacuum arc coating apparatus providing an off sight electron beamevaporation hot cathode (EBEHC) arc plasma source within the plasmaduct,

[0060]FIG. 8n is a schematic plan view of a dual filtered cathodicvacuum arc apparatus providing an off-sight electron beam evaporationhot anode A) arc plasma source within the plasma duct,

[0061]FIG. 9 is a schematic plan view of an embodiment of a vacuum arccoating apparatus with a getter pumping system, showing the deflectingelectromagnetic fields produced by the deflecting and focusing magneticcoils,

[0062]FIG. 10 is a graph illustrating the relationship between therepelling electrode voltage and the ion current as a function of therepelling electrode current in the arc coating apparatus of theinvention,

[0063]FIG. 11 is a graph illustrating coating thickness distribution asa function of the distance of the substrates from the top in the arccoating apparatus of FIG. 8c,

[0064]FIG. 12 is a schematic plan view of an embodiment of a vacuum arccoating apparatus utilizing filtered arc sources with an additionalfiltration stage,

[0065]FIG. 13 is a schematic illustration of a preferred thermal barriercoating architecture,

[0066]FIG. 14 is a graph illustrating operating pressure ranges forvarious plasma surface engineering processes,

[0067]FIG. 15 is a schematic illustration of an embodiment of a filteredarc coating apparatus utilizing a substrate holder connected to abi-polar DC power supply, and

[0068]FIG. 16 is a graph illustrating a DC pulse bias voltage of thesubstrate holder generated by embodiment of FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

[0069]FIG. 1 illustrates a prior art apparatus for the application ofcoatings in a vacuum. The apparatus comprises a plasma source comprisingcathode 12 disposed in a cathode chamber 14 in communication with aplasma duct 16 in the form of a parallelepiped. Cathode 12 is surroundedby focusing and stabilizing electromagnets 13, and anodes 18 aredisposed on planes of the cathode chamber 14 adjacent to the cathode 12to create an electric arc discharge when current source 19 is activated.

[0070] A deflecting magnetic system comprises a rectangular coil 20formed from linear conductors surrounding the plasma duct 16. A focusingcoil 21 may also be provided surrounding the plasma duct 16. The plasmaduct 16 is in communication with a coating chamber (not shown), in whicha substrate holder (not shown) supporting the substrates (not shown) ispositioned. The substrate holder is thus located off of the optical axisof the cathode 12, preferably at approximately a right angle, tominimize the flow of neutral particles toward the substrates.

[0071] On the walls of plasma duct 16 are mounted plate electrodes 24,26 provided with diaphragm filters, spaced from the walls of the plasmaduct 16 and electrically insulated therefrom, for deflecting the flow ofplasma away from the optical axis of the cathode 12 and through theplasma duct 16. In the embodiment shown deflecting electrode 26 islocated on a parallelepiped wall opposite the cathode 12. Deflectingelectrode 26 may optionally be located on any wall adjoining the wall onwhich the cathode 12 is positioned. In these positions, electrode 26serves both as a baffle which traps macroparticles and as a deflectingelement which redirects the plasma stream toward the substrates.

[0072] Deflecting electrode 26 is shown spaced from the wall of theplasma duct 16, which permits a flow of plasma behind the electrode 26.The deflecting electrode 26 may be at floating potential, or isoptionally positively biased by connecting it to the positive pole of anauxiliary current source 26 a as shown. Deflecting electrode 24 is shownat a floating potential.

[0073] In the prior art apparatus of FIG. 1 a substantial part of thesurface of deflecting electrode 26 is disposed outside of the cusp ofthe magnetic field generated by deflecting coil 20, i.e. in thedeflection region of the plasma duct 16, where the tangential componentof the magnetic field generated by the deflecting coil 20 is relativelysmall. Although the magnetic field does not influence ions directly, astrong tangential magnetic field confines electron clouds which createsan electric field that repels ions. Thus, in the deflecting region theelectric field generated by deflecting electrode 26 has little influenceon ions entrained in the plasma stream, and ions tend to accumulate onthe electrode 26 because the residual component of their momentum alongthe optical axis of the cathode 12 exceeds the deflecting force of thedeflecting field generated by deflecting electrode 26.

[0074]FIG. 2 illustrates a first preferred embodiment of the presentinvention utilizing a filtered arc source containing a single cathode 12disposed in a cathode chamber 14 in communication with a plasma duct 16.The cathode chamber 14 is surrounded by focusing and stabilizingelectromagnets 13, and anodes 18 are disposed on planes of the cathodechamber 14 adjacent to the cathode 12 a and connected to DC power source19, as in the prior art apparatus.

[0075] The deflecting magnetic system comprises rectangular coil 20surrounding the plasma duct 16, and a focusing coil 21 is providedsurrounding the plasma duct 16 downstream of the deflecting coil 20. Asin the prior art the plasma duct 16 is in communication with a substratechamber 10 containing the substrate holder 2, positioned off of theoptical axis of the cathode 12.

[0076] According to the invention the apparatus is provided with atleast one deflecting electrode 30 and at least one repelling electrode32.

[0077] The deflecting electrode 30 is insulated from the wall of theplasma duct 16 as by insulating spacer 31 and preferably comprises agenerally planar conductive plate 30 a, optionally with diaphragmfilters 30 b located on the optically exposed surfaces of the plate 30 aand disposed obliquely relative thereto. In the embodiment shown thedeflecting electrode 30 can be considered to consist of either twoseparate electrode sections 30′, 30″ which are electrically connectedtogether at the corner of the plasma duct 16, or as a single deflectingelectrode 30 with orthogonal sections 30′, 30″ configured to generallyconform to the interior surface of the adjoining walls of the plasmaduct 16. The deflecting electrode 30 is preferably spaced from the wallsof the plasma duct 16 to minimize obstruction to the flow of plasmathrough the plasma duct 16, and may be maintained at a floatingpotential, or optionally positively biased by connection to an auxiliarypower source 26 b as shown. It is also possible to use the primarycurrent source 19 both to generate an arc current between the cathode 12and anodes 18 and to bias the deflecting electrode 30.

[0078] Most of the deflecting electrode 30 is positioned in thedeflecting portion of the plasma duct 16, in which the tangentialcomponent of the magnetic field generated by the deflecting coil 20 isrelatively small. This significantly reduces the effectiveness of thedeflecting electrode 30. The deflecting influence of the deflectingelectrode 30 can be enhanced by increasing the current applied to theelectrode 30, but increasing the current also increases the incidence ofarc spot generation and erosion of the cathode 12, which would result ina much higher macroparticle density with little corresponding increasein ion yield at the substrate. Moreover, this commensurately increasesthe risk of short-circuiting the arc current.

[0079] Thus, according to the invention a separate repelling electrode32, electrically isolated from the deflecting electrode 30, ispositioned downstream of the deflecting electrode 30 where thetransversal component of the magnetic field generated by the deflectingmagnetic coil 20 is weakest and the tangential component of the magneticfield is strongest. The repelling electrode 32 is electrically isolatedfrom the deflecting electrode, which facilitates independent control ofthe bias potential on the repelling electrode 32. In the embodimentshown repelling electrode 30 is biased through connection to anauxiliary DC current source 26 a.

[0080] In operation, the substrates 4 are mounted on the substrateholder 2 in the coating chamber 10. The apparatus is evacuated to thedesired pressure using conventional techniques and vacuum pumpingapparatus well known to those skilled in the art. The primary currentsource 19 is activated, creating an arc discharge between the cathode 12and anodes 18 which begins to evaporate the cathodic material into thecathode chamber 14. At the same time, or after a selected time intervalas desired, the auxiliary current source 26 a is energized to bias therepelling electrode 32, creating an electric field of relatively uniformintensity along the wall of the plasma duct 16 opposite the cathodechamber 14.

[0081] Cathodic evaporate is ejected from cathode 12 in an ionizedplasma containing both ionized coating particles and neutral contaminateor macroparticles. The plasma is focused by the magnetic focusing coils13 and flows past the anodes 18, as is conventional. The plasma stream,with entrained macroparticles vaporized from the evaporation surface ofthe cathode 12, is thus ejected toward the deflecting electrode 30. Themagnetic deflecting coil 20 generates a magnetic field which directs theplasma stream and ions of coating material suspended therein through theplasma duct 16 toward the coating chamber 10, as shown by the arrows inFIG. 2. Neutral macroparticles remain unaffected by the deflectingmagnetic field and the electric fields generated around deflectingelectrode 30 and repelling electrode 32, and continue in a pathgenerally along the optical axis of the cathode 12, striking thedeflecting electrode 30 and either adhering to the electrode 30 orfalling to the bottom of the apparatus.

[0082] The primary cathodic arc source installed in cathode chamber 14can be similar to the plasma source described in U.S. Pat. No. 3,793,179issued Feb. 19, 1974 to Sablev, which is incorporated herein byreference. This plasma source utilizes a circular cylinder target. Tocover a large area coating zone several cathodic arc sources withcylindrical targets can be installed on the side wall of the cathodechamber 14. The primary cathodic arc source can be of rectangulardesign, as was described in U.S. Pat. No. 5,380,421 issued Jan. 10, 1995to V. Gorokhovsky or in International Patent Application No.PCT/CA00/00380, which are incorporated herein by reference. In this casethe cathode target is rectangular covering entire coating zone.

[0083] It will be appreciated that because the plasma cannot traversethe deflecting magnetic field lines, in order to fully utilize thecathode target the magnetic cusp generated by the deflecting conductor20 a must be oriented toward the coating chamber 42, to guide the plasmastream toward the coating chamber 42. An opposite cusp, which would leadthe plasma stream in a direction opposite the coating chamber, iscreated by the closing conductors 20 b of the deflecting coils 20, asshown in FIG. 3b; thus, the closing conductors 20 b are maintainedremote from the filtered arc source, and the cathodes 12 must bepositioned within the cusp of the magnetic field generated by thedeflecting conductor 20 a of the deflecting coil 20. Any portion of theplasma outside of the cusp of the deflecting magnetic field will bedeflected into the back wall (behind the deflecting electrode portion30′) of the cathode chamber 14, and will not reach the substrates 4.

[0084] The use of linear deflecting and focusing conductors 20 a, 21allows the plasma duct to be of virtually unlimited length. The linearconductors 20 a, 21 each generate a cusp of magnetic field lines whichcurves in two-dimensions, along the direction of plasma flow, but has aheight which is limited only by the length of the linear conductors 20 aand 21, which allows for the coating of substrates 4 of considerablylarger dimensions as described in U.S. Pat. No. 5,435,900 toGorokhovsky, which is incorporated herein by reference. The deflectingand focusing magnetic fields are thus quasi-two dimensional, in that thecross-section of the cusp (for example as reflected by the plasma flowlines in FIG. 2) is substantially constant in the third dimension.

[0085] To increase the proportion of ions which reach the substrates,the repelling electrode 32 is preferably biased to a higher positivepotential than the deflecting electrode 30. Thus, although thetangential component of the deflecting magnetic field generated by thedeflecting magnetic coil 20 is weak in the deflecting region containingthe deflecting electrode 30, this can now be compensated for byincreasing the potential applied to, and thus the deflecting effect of,the repelling electrode 32, without risking short circuiting the arccurrent or misdirecting the plasma flow. This is made possible becausethe repelling electrode 32 is disposed in a portion of the plasma ductwhere the tangential magnetic field component is strong.

[0086] A further preferred embodiment of the invention having a filteredarc source with two cathodes 12 at one end of a coating chamber 42 isillustrated in FIG. 3a. In this embodiment a vacuum arc coatingapparatus 40 provides two plasma sources comprising cathodes 12 disposedwithin the filtered arc source comprising cathode chambers 44 positionedon opposite sides of the plasma duct 46. As in the previous embodiment,the cathodes 12 each comprise a cathode plate and are respectivelysurrounded by focusing and stabilizing electromagnets 13, and anodes 18connected to the positive terminal of DC power supply 19. Plasma duct 46is in communication with the coating chamber 42, in which a substrateholder 2 supporting substrates 4 is positioned off of the optical axesof both cathode sources 12. In the embodiment shown substrate holder 2is biased to a negative potential by an independent power supply 26 b.

[0087] In this embodiment a deflecting electrode 50, preferablycomprising an electrode plate 50 a optionally supporting baffles 50 b,is positioned between the plasma sources 12, generally parallel to thedirection of plasma flow through the plasma duct 46, and is isolatedelectrically from the walls of plasma duct 46 by an insulator 51. Aconductive shield or shroud 52 may be provided to serve as a baffle fordeflecting undesirable macroparticles discharged from cathodes 12 and toinsulate the electrode 50 from contaminants. The shroud 52 may beoptionally biased to a negative potential, which provides the advantagesdescribed below.

[0088] The magnetic deflecting system comprises coils 20 havingdeflecting conductors 20 a proximate to the corners of the plasma duct46 adjacent to the cathode chambers 44, and closing conductors 20 b (forexample as shown in FIG. 7) remote from the plasma duct 46 so as not toinfluence the direction of plasma flow.

[0089] The deflecting magnetic fields generated by the conductors 20 adirect the plasma stream toward the substrates 4. As in the previousembodiment, in order to avoid plasma losses the cathodes 12 must bepositioned within the cusps of the magnetic fields generated bydeflecting conductors 20 a of the deflecting coils 20.

[0090] Thus, with a pair of cathodes 12 disposed in a filtered arcsource on opposite sides of the plasma guide 46, at least a portion ofthe deflecting electrode 50, and the repelling electrode 60, aredisposed in alignment with a plane of symmetry between opposite walls ofthe plasma guide 46. The plane of symmetry extends between the magneticcusps generated by deflecting conductors 20 a, and the repellingelectrode 60 is thus positioned between the cusps in a portion of theplasma duct 46 in which the tangential component of the deflectingmagnetic fields is strongest.

[0091] In this embodiment a focusing coil 21 is disposed about theopposite end of the plasma duct 46, for generating focusing magneticfields within the plasma duct 46. The focusing coil 21 may be a singlecoil, for example as shown in FIGS. 3a and 3 b may comprises focusingconductors 21 a disposed near the end of the plasma duct 46 incommunication with the coating chamber 42, the closing conductors 21 btherefor being disposed remote from the plasma duct 46 so as not toinfluence the flow of plasma, as shown in FIG. 7.

[0092] The focusing coil 21 (or focusing conductor 21 a) generates amagnetic focusing field in the same direction as the deflecting magneticfields generated by the deflecting coils 20, as shown in FIG. 9. Withinthe plasma duct 46 the transversal components of the focusing magneticfields generated by the focusing conductor 21 substantially cancel thedeflecting magnetic fields generated by the deflecting coils 20,minimizing the transversal components of these magnetic fields. Thetangential components of these magnetic fields overlap and create asubstantially uniform magnetic wall which confines the plasma streamaway from the walls of the plasma duct 46.

[0093] As can be seen from equation 2 above, in order to increase thestrength of the deflecting electric field the component of the magneticfield which is tangential to the surface of the deflecting electrodemust be enhanced. Enhancing the tangential magnetic field component alsohas the effect of increasing magnetic insulation of the plasma from thedeflecting electrode. However, increasing the strength of the magneticfield itself will cause the plasma stream to be misdirected toward theelectrode, rather than deflected toward the intended target.

[0094] A repelling electrode 60 is thus positioned downstream of thedeflecting electrode 50 within the plasma duct 46, preferably in theregion between deflecting coils 20 and focusing coils 21, where thetransversal component of the magnetic fields is weakest and thetangential component of the magnetic fields is strong. Repellingelectrode 60, which preferably comprises an electrode plate 60 aoptionally supporting baffles 60 b, is biased positively through aconnection with the positive terminal of auxiliary DC power source 26 a.It is advantageous to provide the repelling electrode 60 with a separateauxiliary current source 26 a, either independent or in addition toanother current source (for example 19 as shown in FIG. 3), since therepelling effect of the repelling electrode 60 is directly proportionalto its potential. In the embodiment shown the negative terminal of DCsource 26 a is connected in series with one of the primary power sources19, through diode 27, so that the repelling electrode 60 alwaysmaintains at least the same potential as the anodes 18, and auxiliarypower source 26 a is used to increase the potential of the repellingelectrode 60 beyond the potential of anodes 18. DC sources 19 and 26 amay alternatively be electrically independent.

[0095] An optional focusing electrode 23 may be provided surrounding therepelling electrode 60 near the exit of the plasma duct 46 (along theinner side of the wall of the housing), where the tangential componentof the deflecting/focusing magnetic fields is strongest. Applying apositive potential to this focusing electrode, as shown in FIG. 3a,improves the transversal electric field in the same manner as therepelling electrode 60.

[0096] In the operation of the apparatus of FIG. 3a, the substrates 4 tobe coated are mounted on the substrate holder 2. The cathode chambers 44and adjoining plasma duct 46 and coating chamber 42 are sealed andevacuated to the desired pressure using a conventional vacuum pumpingapparatus (for example as shown in FIG. 4).

[0097] The power sources 19, 26 a and focusing and deflecting coils 13,20 are activated and an arc is ignited between each cathode 12 and itssurrounding anodes 18. The plasma stream is ejected from cathode 12 andfocused within the cathode chamber 44 by focusing electromagnets 13,which also drive the plasma toward the plasma duct 46. Magnetic focusingconductors 20 a generate magnetic fields about the corners of the plasmaduct 46 at the end adjoining the cathode chamber 44, to deflect theplasma stream through the plasma duct 46 and toward the coating chamber42.

[0098] The deflecting magnetic fields generated by the deflectingconductors 20 a deflect ionized components of the plasma towards thecoating chamber 42, while neutral macroparticles remain unaffected and,entrained in the plasma being deflected out of the cathode chambers 44,strike deflecting electrode 50 and either adhere to it or fall to thebottom of the apparatus 40.

[0099] The plasma stream is deflected by deflecting coils 20, assistedby deflecting electrode 50, into the plasma duct 46 where it passesrepelling electrode 60. As can be seen from the magnetic field linesshown in FIG. 8a, the deflecting magnetic fields surrounding thedeflecting conductors 20 a and focusing coil 21 have a strong tangentialcomponent (relative to the plasma stream) inside the plasma duct 46,which acts as a magnetic “wall” to isolate the walls of the plasma duct46 from the plasma flow.

[0100] However, as the plasma flows between deflecting coils 20 andfocusing coil 21, because the magnetic fields generated by coils 20, 21traverse the walls of the plasma duct 46 in the same direction, in theregion of overlap the transversal components of these deflectingmagnetic fields substantially cancel and the tangential components aresuperposed to create a strong tangential magnetic “wall” which isolatesthe plasma from the wall of the plasma duct 46. In this region therepelling electrode 60 creates a strong electric field in a directiongenerally perpendicular to the plasma stream, which repels ions towardthe walls of the plasma duct 46. The plasma is thus confined by theelectric field generated by the repelling anode 60 and the magneticfields generated by the deflecting and focusing magnetic coils 20, 21.This divides the plasma stream into two portions, one on either side ofthe repelling anode 60, which flow along the plasma duct 46 and mergedownstream of the repelling electrode. This drives the plasma stream ina helical path toward the coating chamber 42, promoting a uniform plasmastream with a high ionization density entering the coating chamber 42.

[0101] The primary or “proximal” anodes 18 generate an arc which erodesthe cathode 12 and creates a plasma for coating the substrates 4. Thedeflecting electrode 50 and repelling electrode 60 constitute“intermediate” auxiliary anodes, which deflect and repel the plasmastream within the cathode chamber 44 and plasma duct 46, and indual-cathode embodiments divide the plasma stream as described above.FIG. 3a also illustrates a “distal” anode 70 disposed within the coatingchamber 42, in this embodiment positioned on the side of substrateholder 2 opposite the plasma duct. The distal anode 70 assists in thedeflection of the plasma stream in the direction of the substrates 4before the plasma is pumped out of the apparatus 40. Preferably thedistal anode 70 is energized by power sources 26 b connected between thecathode 12 and the distal anode 70 (and optionally also by a separatepower source 26 c isolated by diodes 31), so that distal anode 70 alwaysmaintains at least the same potential as the repelling electrode 60, andauxiliary power source 26 b is used to increase the potential of thedistal anode 70 beyond the potential of repelling electrode 60.

[0102] The embodiment of FIG. 3b thus provides a chain of anodes,proximal anodes 18 local to the cathodes 12; medial anodes such as therepelling electrode 60 and focusing electrode 23, contained within theplasma duct 46, and distal anodes such as the anode 70, which may bedisposed anywhere within the coating chamber 42. These anodes combine tocreate a desired dispersion of electrons and a uniform plasma cloud inthe vicinity of the substrates 4. The anodes could be connected toindependent power supplies, however this would result in high powerconsumption. The chain of anodes can alternatively be connected to thesame power supply and rastered. Ionization of the plasma is maximized inthe vicinity of an active anode, and rastering through the chain ofanodes in this fashion allows for considerable conservation of powerwhile maintaining a high plasma ionization level and mixing the plasmathroughout the apparatus to create a uniform plasma immersedenvironment.

[0103]FIG. 3b illustrates a variation of the embodiment of FIG. 3a, inwhich a filtered arc source, each containing a pair of cathodes 12, isprovided on both sides of the coating chamber 42. This embodiment can beused for plasma immersed treatment of substrates 4, by selectivelydeactivating the deflecting coil 20 and focusing conductor 21 on oneside of the coating chamber 42. When all plasma sources 12 are active,plasma streams are generated in both cathode chambers 44. However, whilethe plasma stream generated on the side of active coils 20, 21 is guidedinto the coating chamber 42 by the deflecting and focusing magneticfields, the particulate (metal vapour plasma) component of the plasmastream on the side of the inactive coils 20, 21 remains largely confinedwithin the cathode chambers 44, there being no magnetic drivinginfluence on that side of the coating chamber 42. The cathodes 12 on theside of the inactive coils 20, 21 thus serve as powerful electronemitters, improving ionization of the gaseous component of the plasmaflowing past shutter 80 a and into the coating chamber 42, andsignificantly improving the properties of the resulting coating.

[0104] In this embodiment the filtered arc source on the side of thecoating chamber 42 with the deactivated coils 20, 21 is used foremitting electrons to provide a plasma immersed environment for coatingsdeposited by the other filtered arc source or, as in the embodiment ofFIG. 8b, magnetron arc sources, or both. This embodiment of theapparatus can thus be used for any plasma-immersed process, includingplasma assisted low pressure chemical vapor deposition (PALPCVD)processes.

[0105] Where a particularly contaminant-free coating is required, loadlock shutters 80 a, 80 b may be disposed between each plasma duct 46 andthe coating chamber 42. Each load lock shutter 80 a, 80 b comprises agrid made of stainless steel or another suitable metal having barspreferably between one-half inch and one inch in diameter and one-halfinch to one inch openings between the bars, for example as shown in U.S.Pat. No. 5,587,207 issued Dec. 24, 1996 to Gorokhovsky, which isincorporated herein by reference. The load lock shutters 80 may beactuated manually, mechanically, or electrically, and are impervious tothe particulate components of the plasma stream (ions and straymacroparticles) but pervious to electrons. Thus, to ensure that strayparticles from the side of the inactive coils 20, 21 do not disperseinto the coating chamber 42, the load lock shutters 80 a, 80 b areselectively independently closed or opened to respectively block orpermit a flow of ions and stray macroparticles through to the coatingchamber 42

[0106] For example, as shown in FIG. 3b the shutter 80 a can be openedwhile shutter 80 b remains closed. All plasma sources 12 are active, andthus plasma streams are generated in both cathode chambers 44. However,while the plasma stream generated on the side of the open shutter 80 afreely flows into the coating chamber 42, the particulate component ofthe plasma stream on the side of the closed shutter 80 b remainsconfined within the cathode chamber 44 and plasma duct 46, upstream ofthe shutter 80 b, both by the absence of deflecting and focusingmagnetic fields and by the barrier created by the load lock shutter 80b.

[0107] The load lock shutters 80 a, 80 b may be maintained at a floatingpotential, or a strong negative potential may be applied in which casethe load lock shutter 80 a or 80 b will also serve as an ionaccelerator, actively forcing positive ions generated by cathodic arcsources inside of plasma guide chamber, into the coating chamber 42 in amanner similar to a Kaufman type ion beam source. Diagnostic ports 84may optionally be provided to accommodate sensors and/or probes formonitoring the environment within the coating chamber 42.

[0108] This embodiment of the apparatus can thus be used for anyplasma-immersed process, including plasma assisted chemical vapordeposition (CVD) processes. To facilitate plasma immersed processes, thedistal auxiliary anodes 70 surround the rotating substrate holder 2, andthereby help to disperse the plasma uniformly within the coating chamber42, for example as shown by the plasma flow lines in FIG. 8a, byattracting the ionized gaseous component to all portions of the coatingchamber walls.

[0109] The operation of this embodiment is similar to the operation ofthe embodiment of FIG. 3a, except that in this embodiment the deflectingcoils 20 and focusing coil 21 on the side of the closed load lockshutter 80 b are deactivated during the plasma immersed process, so thatthe plasma is not driven through the plasma duct 46 on that side of theapparatus. Even without the load lock shutters 80 a, 80 b the plasma onthe side of the apparatus in which the deflecting coils 20 and focusingcoil 21 are deactivated will remain largely confined within the filteredarc source, there being no electromagnetic influence to drive the plasmaout of the cathode chamber 44. Electrons will disperse into the plasmaduct 46 and coating chamber 42. The closed load lock shutter 80 bassists in maintaining the purity of the coating by completely excludingstray ions and macroparticles from entering the coating chamber 42,however the load lock shutters 80 a, 80 b are not strictly necessary forall plasma immersed applications. It should also be noted that theembodiment of FIG. 3a provides proximal anodes 18 for generating an arcdischarge at the cathodes 12, whereas in the embodiment of FIG. 8a thepositive pole of the power source 19 for the cathode 12 is grounded sothat the cathode chamber housing serves as a proximal anode for thecathode 12.

[0110] Also, the embodiment of FIG. 8a provides magnetic deflectingcoils 71 surrounding the distal auxiliary anodes 70, which serve todeflect the plasma flow past the substrates 4 within the coating chamber42. The magnetic fields generated by deflecting coils 71 extend wellbeyond the electric fields generated by the auxiliary anodes 70, and theplasma flow is dispersed along the magnetic field lines produced bydeflecting coils 71. In order to ensure that the plasma is dispersedtoward the auxiliary anodes 70, the magnetic fields generated by thedeflecting magnetic coils 71 should be oriented in the same direction asthe focusing magnetic fields generated by the focusing coils 21. Thecoils 71 surrounding anodes 70 also allow for the redirection of theplasma flow from one distal anode 70 to another, and the plasma flow canthus be rastered within the coating chamber 42 for a more even coatingon the substrates 4.

[0111] The distal auxiliary anodes 70 can be disposed tangential to themagnetic force lines generated by the deflecting magnetic coils 71,which increases the anode voltage drop and transfers more energy intothe plasma; or the distal auxiliary anodes 70 can be disposedtransversely to the magnetic force lines generated by the deflectingmagnetic coils 71, which to increase the stability of the auxiliary arcdischarge and the uniformity of plasma distribution. A plurality ofdistal auxiliary anodes 70 can be positioned to provide a combination oftangential and transversal anode surfaces, and switching the arc currentbetween these anodes 70 creates a plasma blender, which equalizes theplasma treatment of the substrates 4.

[0112] One of the problems that appears during deposition of coating ina dense strongly ionized plasma is micro-arcing on substrates. When thesubstrate bias voltage exceeds the voltage drop associated with thevacuum arc discharge, arc breakdown can result in creating arc spotsthat damage the surface of the substrates to be coated. To eliminatethis problem, the direction of the current conveyed by the plasmaenvironment to the substrate surface has to be reversed with repetitionfrequency exceeding the characteristic frequency of vacuum arcbreakdown. In a further embodiment of the invention, illustrated in FIG.15, a DC bias power supply having positive and negative poles (notshown) is connected to the substrate holder 2 via a switchingarrangement 501,502 utilizing fast switching solid state elements suchas IGBTs or the like. The switching cycle is controlled by a low voltagecontrol device (not shown). This connects the substrate holder 2alternately to the positive and negative poles of the bias power supply.The substrate holder 2 can be connected to the negative pole by openingthe pair of switches 501 a, 502 b and closing the pair of switches 501b, 502 a. Then the substrate holder 2 can be connected to the positivepole of power supply by opening the pair of switches 501 b, 502 a andclosing the pair of switches 501 a, 502 b.

[0113] Instead of connecting the substrate holder 2 to the positive poleof a separate power supply, it can be connected to the distal auxiliaryanode 601. An example of the shape of the bias voltage and bias currentcreated by this arrangement is shown in FIG. 16. In this example therepetition frequency of pulse bias is 100 kHz, which determines theperiod of pulse to be τ_(p)=10 μm. The bias voltage V_(bias) is negativeat the value of −240V during first 6 μm of the pulse period whensubstrate holder is switched to the negative pole of bias power supply.At this point the bias current is determined mostly by ions conveyed bythe plasma to the substrate surface. The ion current density is given byi_(i)˜c_(e)q_(e)n_(e)(2kT_(e)/m_(i))^(1/2), where m_(i) is mass of ion,T_(e) is electron temperature, k is Boltzmann constant, q_(e) is chargeof electron, c is the constant c˜1. The characteristic ion currentdensity does not exceed 10 mA/cm² when the total current of all primarycathodic arc sources reaches 500 amperes. At this point metal-gaseousions bombard the substrate surface with an energy E=q_(ion)V_(bias),where q_(ion) is the charge of ions. In the remainder of the pulseperiod the bias voltage becomes positive as a result of switching theconnection of the substrate holder 2 to the positive pole of bias powersupply or to distal anode 601. At this point the bias voltage does notexceed 5 volts, but the bias current, created mostly by electronsconveyed by plasma to the substrate surface, exceeds 100 amperes withreversed direction in relation to the ion current. The bias electroncurrent conveyed by plasma to substrates can be determined asI_(be)˜i_(e)A_(s), where i_(e) is density of the current of thermalizedelectrons in plasma, A_(s) is substrate area. The density of the currentof thermalized electrons generated by plasma environment is given byi_(e)={fraction (1/4)}q_(e)n_(e)<v_(Te)>, where n_(e) is plasma density,<v_(Te)> is average velocity of thermalized electrons in plasma. In arcplasma the velocity of thermalized electrons is given by <v_(Te)>˜(8kT_(e)/πm_(e))^(1/2) where me is mass of electron. This gives theorder-of-magnitude estimation of total electron current which can becollected in high current arc plasma as 10-50 kA. The portion of theelectron current which can be collected by the substrates 4 consists of0.1% to 10% of the total electron current and typically ranges from 100to 500 amperes. When the substrate reaches an electron current at alevel comparable to the arc current, cathodic arc spots can no longerexist on the substrate surface. It was found that the ratioi_(e)/i_(i)>10 during positive part of pulse period with repetitionfrequency f>10 kHz allows for the substantially complete elimination ofthe problem of arc breakdown on substrates, commonly known as“micro-arcing.” In an apparatus with a single dual-cathode filtered arcsource having first and second cathodes 12 installed on opposite walls,for example the embodiment of FIG. 8a, it is not possible to generateions from one cathode 12 and electrons from the other cathode 12, sincethe filtered arc source can generate only one type of particle at atime: either ions or electrons, depending on whether its associateddeflecting system is activated (to generate metal ions) or deactivated(to generate electrons). When the cathodic arc sources are activated thefiltered arc source can generate electrons by creating an auxiliary arcdischarge between the cathode 12 and the distal anode 70 disposed in thecoating chamber 42. Thus, in a filtered arc coating mode the filteredarc source will generate metal ions, while in the auxiliary arcdischarge mode the filtered arc source will generate electrons toprovide plasma immersed environment for ion cleaning (etching), ionnitriding, ion implantation, and plasma assisted low pressure CVD(PALPCVD) processes.

[0114] It is however possible to provide load lock shutters 80 c, 80 dbetween the filtered arc source and the plasma duct 46, for example asshown in phantom in FIG. 3b, each load lock shutter 80 c or 80 d beingpositioned such that when closed it blocks the magnetic cusp generatedby the deflecting magnetic system only on one side of the plasma duct46. Cathodic evaporate from the cathode 12 on that side of the filteredarc source, being trapped within the magnetic cusp, will thus beconfined within the filtered arc source by the load lock shutter 80 c or80 d, while cathodic evaporate from the cathode 12 on the other side ofthe filtered arc source will flow along the (unblocked) magnetic cuspinto the plasma duct. This creates a plasma immersed environment from asingle dual-cathode filtered plasma source, and/or allows for thesequential deposition of coatings of different types on the substrates4. When the load lock shutters 80 c, 80 d installed at the exit of afiltered arc source are charged with negative potential, they functionas a positive ion beam source (ion extractor), in which case a preferredsize of the openings in the load lock shutter is in the range of 100 μmto 1000 μm. When set up with a floating or slightly positive potential,the load lock shutters 80 c, 80 d become transparent to the electrons ofthe auxiliary arc discharge, flowing between the cathode 12 of thefiltered arc source and the distal auxiliary anode(s) 70 installed inthe coating chamber 42.

[0115] This positioning of the load lock shutters 80 c, 80 d between thefiltered arc source and the plasma guide 46 can also be implemented inthe single-filtered arc plasma source embodiments, for example theembodiment of FIG. 8b, either in addition to or instead of the load lockshutters 80 a, 80 b shown between the plasma duct 46 and the coatingchamber 42. As shown in phantom in FIG. 3b, a load lock shutter 80 e canalso be positioned between any cathode 12 and its adjacent deflectingelectrode 50 in a filtered arc source, to block cathodic evaporate fromreaching the deflecting electrode 50 and provide an extremely cleanelectron flow with virtually no metal vapor dispersion into the plasmaduct 46. This can be important in processes such as semiconductorapplications, where even a very low metal vapor component cancontaminate the substrates 4.

[0116] Rastering through the chain of proximal-medial-distal anodes inthese embodiments allows for the opportunity to sustain the arc betweenanodes in different stages of the apparatus, which cleans the plasmaflow in each stage and draws electrons into the next stage for amaximized plasma immersed environment.

[0117] It is also possible to provide different metal target in theopposed cathodes 12 of a single filtered arc source, to allow thedeposit composite coatings. For instance, in the apparatus of FIG. 8bthe evaporation surface of one cathode 12 can be titanium and theevaporation surface of the other cathode 12 can be aluminum, and withthe introduction of gaseous nitrogen can produce a composite TiAlNcoating. Using the same evaporation surface for one filtered arc source,but different evaporation surfaces for other filtered arc sources(installed on the different walls of coating chamber) allows for thedeposit of multi-layer coatings like TiN/CrN. Where the differentevaporation surfaces are employed in the same filtered arc source(installed on the opposed cathodes 12) a composite coating (such asTiCrN) can be obtained. This is an important advantage in the use ofmultiple-cathodes and multiple-filtered arc sources.

[0118] It will also be appreciated that in a multiple-filtered arcsource embodiment, such as the embodiment of FIG. 3b, the cathodes 12 ofdifferent cathode pairs (i.e. different filtered arc sources) can becomposed of different materials. Accordingly, by selectivelydeactivating the deflecting coils 20 and focusing coil 21 on one side ofthe apparatus (and optionally opening and closing the load lock shutters80 a, 80 b) it is possible to apply two different types of coatings tothe substrates 4, each in a plasma immersed environment.

[0119]FIGS. 8b and 8 c illustrate a still further variation of thisembodiment, in which the distal auxiliary anodes 70 also serve as anodesfor magnetron arc plasma sources 90 disposed within the coating chamber42, optionally surrounded by focusing/steering coils 92. In theseembodiments a dense plasma can be generated within the coating chamber42 by the combination of plasma streams from the cathodes 12 and plasmastreams from the magnetrons 90. The magnetrons 90 may be maintained at ahigh negative potential by grounding the positive pole of the magnetronpower source, as illustrated in FIG. 8b, or may be provided with aseparate power source 94 as illustrated in FIG. 8c. In both of theseembodiments the magnetrons 90 may constitute the primary source ofcathodic material, and the cathodes 12 can serve as electron emitters,in the manner previously described, by deactivating the deflecting coils20 and focusing coil 21 and optionally providing load lock shutters (notshown) between the plasma duct 46 and the coating chamber 42.

[0120] The main disadvantage of magnetron sputtering is a relatively lowionization degree (1 to 3%) and, as a result, a low ion bombardment rateof the substrate 4 to be coated. That leads to poor structure and lowadherence of coatings. In addition, the productivity of this process isproportional to the concentration of sputtering gas ions (usually Ar⁺ions), which have a high sputter rate and also cause sputtering of thesubstrates 4. For example, U.S. Pat. No. 5,160,595 to Hauzer proposes anarc/magnetron coating deposition method in which an edge magnetarrangement is displaceable in the axial direction relative to apreferably fixedly mounted center pole permanent magnet. In thisapparatus a cathode sputtering process and/or cathodic arc evaporationprocess can be achieved depending upon the relative position of the edgemagnet arrangement and the center pole magnet. During the transitionfrom arc operation to magnetron operation, both the low voltage powersupply supporting the arc mode and the high voltage power supplysupporting the magnetron mode are enabled, to create discharge betweennegative charged target and positive charged anode. As a rule the arcmode is used only for the ion cleaning stage of process. The principaldisadvantages of this process is the presence of microparticles of thecathode material in the vapor stream in an arc mode, and a relativelylow ionization of sputtered target atoms in the magnetron mode.

[0121] The embodiments of FIGS. 8b and 8 c overcome these disadvantagesby providing a filtered arc plasma immersed magnetron apparatus having aseparate cathodes 12 installed in the filtered arc source and magnetroncathodes 90 installed in the coating chamber 42 off of the optical axisof the arc cathodes 12. The distal auxiliary anodes 70 can be installedanywhere in the coating chamber 42, but preferably are disposed in thevicinity of the magnetron sources 90, surrounding the magnetron targets.The distal auxiliary anodes 70 in this configuration thus also serve asarc/magnetron anodes, which are common to both the cathodic arc plasmasource 12 (as a distal auxiliary anode 70) and as a magnetron anode forthe magnetron source 90 to thereby create both arc-discharge andmagnetron-discharge simultaneously. This “arc enhancement magnetrondischarge”, which is essentially the magnetron discharge immersed inhighly ionized filtered arc plasma environment, provides the bestfeatures of both types of discharges: a high rate of ionization throughthe arc discharge process and high rate of target atomization throughthe magnetron sputtering process.

[0122]FIG. 8d illustrate a still further variation of the embodiment ofFIGS. 8b and 8 c, in which one of the distal auxiliary anodes 70 a (thebottom one) also serves as a crucible for evaporation metals 71 havinglow or moderate melting points, optionally surrounded byfocusing/steering coils 92. In these embodiments a dense plasma can begenerated within the coating chamber 42 by the combination of plasmastreams from the cathodes 12 and plasma stream from the resistiveevaporation hot anode-crucible (REHA) arc plasma source 75, heated bythe anode arc current and regular resistance heaters 101. The shield 110may be maintained around the crucible 70 a to restrict theanode-evaporating zone. For the same purpose, the internal part of thesidewall of the REHA's crucible can be made of insulating ceramic as ofalumina or boron nitride (not shown). Concentrating the auxiliary anodicarc plasma on the surface of evaporating metal results in increase ofionization rate of metal vapor plasma, generated by the REHA arc plasmasource 70 a. The cathodes 12 can serve as electron emitters, in themanner previously described, by deactivating the deflecting coils 20 andfocusing coil 21 and optionally providing load lock shutters (not shown)between the plasma duct 46 and the coating chamber 42. Alternatively,the cathodes 12 can supply additional filtered arc plasma stream tomerge with metal vapor plasma stream coming from the REHA-crucible 70 a.

[0123] In a preferred variation of this embodiment, illustrated in FIG.8e, the REHA—metal vapor plasma source 75 is installed inside of theplasma duct 46 of the dual cathode filtered arc source in the area wherethe deflecting magnetic field is smallest, which is the central area ofthe deflecting magnetic field cusp. In this case the metal vapor will bepartially ionized by interaction with anode arc plasma and propagatestoward the substrate to be coated along magnetic field lines of thedeflecting magnetic field. Diffusion losses of metal vapor plasma arewell suppressed by the convex magnetic field of the deflecting magneticcusp.

[0124] In a further variation of this embodiment, illustrated in FIG.8f, an electron beam evaporator is used instead of a resistance heaterto evaporate metal from the anode-crucible 70 a. The electron beam 125generated by thermoionic cathode 130 is turned on to 270 degrees by amagnetic field transversal to the plane of FIG. 8f. This is important inthis embodiment of the invention, to keep the electron beam in thevicinity of the centre of the deflecting magnetic field cusp, whereintensity of the deflecting magnetic field is negligible and does notinfluence the trajectory of electron beam 125. This device optionallyprovides a compensating magnetic coil 140, surrounding the electron beamevaporator, to correct the trajectory of the electron beam 125 to ensurethat it strikes the evaporating metal in the crucible. The ionization ofmetal vapor will increase by maintaining the crucible at anodepotential, while the shield 110 can be insulated and have a floatingpotential. In this mode, depicted as E-Beam Heated Evaporation Anode(EBHEA), an anodic arc spot will be created on the surface ofevaporating metal in the anode-crucible, boosting the ionization rate ofmetal evaporate to more than 60% for metals having low and mediummelting points. The metal vapor plasma then merges with the cathodic arcplasma generated by cathodes 12 and flows toward the substrate to becoated. The focusing electrode 23 has to be installed on the exit ofplasma duct 46 adjacent to the main vacuum chamber 42, to repel metalions and focus the metal plasma flow toward substrate to be coated.

[0125] In the case of evaporating refractory metals, the crucible in theelectron beam evaporator can be maintained at cathode potential whilethe surrounding shield can serve as a local proximal anode, as isillustrated in FIG. 8g. In this mode, depicted as E-Beam HeatedEvaporation Cathode (EBHEC), the ionization rate of metal vapor canreach 90 to 100% by creating a diffused cathodic arc spot in the placewhere the electron beam impact evaporates metal in the crucible-cathode.

[0126] In a further embodiment of the invention, illustrated in FIG. 8h,the resistive evaporator, having a REHA-crucible with evaporating metal,is placed below the centre of the deflecting magnetic cusp on a side ofthe cusp opposite to the main chamber containing the substrates to becoated. In this case, part of the plasma stream generated by cathodes 12is focused toward the crucible, which allows for an increased ionizationrate of metal vapor up to 90%.

[0127] In a further embodiment of the invention, illustrated in FIG. 8i,a resistive evaporator 75 is placed in the centre of a carousel-typesubstrate holder in the main chamber. In this embodiment the distancebetween the crucible 70 a with evaporating metal 71 and the surroundingsubstrates to be coated can be minimal, which is especially advantageousfor evaporating precision metals (Au, Pt, Pd, etc.). The crucible 70 acan be maintained at floating potential or optionally connected to thepositive pole of the auxiliary anode power supply (not shown), whichmakes it a resistive evaporating hot anode (REHA) device.

[0128]FIGS. 8k and l illustrate a still further variation of theembodiments of FIGS. 8a, 8 b, 8 c and 8 d, in which e-beam evaporators170 a, magnetrons 190 and a resistance evaporator 170 b are placed in asubstrate chamber 10 for plasma immersion co-deposition of differentmaterials in highly ionized filtered arc plasma environment. In thisembodiment of the invention e-beam evaporators are installed near a wallof the substrate chamber 10 either opposite or adjacent to the exitopening 14 a of the cathode chamber 14 containing the filtered arcsource comprising cathodes 12. In this case the focusing and deflectingmagnetic fields of the filtered arc source will not affect the positionof the electron beam, or consequently the position of the evaporatingspot on the surface of the material to be evaporated in the e-beamevaporator crucible 70 a. Positioning e-beam evaporators 170 a as wellas thermal resistance evaporators 75 in front of the auxiliary anode 70increases the ionization of metal vapor generated by the metal vaporsources. In the case of distributed anodic arc discharge, any crucible170 a connected to the positive pole of the arc power supply 19 has tobe shielded so that only the evaporated material area is exposed to thearc plasma environment. The magnetrons 190 also can be installed bothadjacent to or opposite to the exit flange 14 a of the filtered arcsource in cathode chamber 14, in the line of sight of the substrates 4.In both cases the filtered arc plasma stream will cross the magnetrontargets providing maximum efficiency of ionization and activation ofmagnetron sputtering flow. The preferable type of magnetron sputteringsource used in this embodiment of the invention is an unbalancedmagnetron, which can be coupled with the exit focusing coil 21 of themagnetic deflecting system of the filtered arc source.

[0129] In operation of the filtered arc immersion sputtering embodiment,the total gas pressure ranges between 1 and 10⁻² Pa, preferably between5×10⁻¹ and 5×10⁻² Pa. The filtered arc source can operate in aco-deposition mode providing a fully ionized metal vapor plasma flow inconjunction with magnetron sputtering deposition. In a plasma immersiondeposition mode the deflecting magnetic field of the filtered arc sourceis turned off and an auxiliary arc discharge is established between oneor both cathode targets of the primary cathodic arc sources 12 of thefiltered arc source and auxiliary anodes 70 disposed in the substratechamber 10. This allows for increased ionization and activation of boththe gaseous and metal atoms components of the magnetron sputtering flow.

[0130] In case of e-beam or thermal resistance evaporation, the totalgas pressure ranges between 1 and 10⁻⁴ Pa. In case of metal coatingdeposition process the total residual gas pressure can be set at a valuebelow 10⁻³ Pa, while in case of reactive evaporation the reactive gaspressure can range between 5×10⁻¹ and 5×10⁻³ Pa.

[0131] In a further embodiment of the invention, illustrated in FIGS. 8mand 8 n, a metal vapor source 75 disposed in the cathode chamber 14′(shown at the bottom of the figures) of the filtered arc source assemblyadjacent to the substrate chamber 10 off sight with substrates to becoated. In this embodiment the opposite cathode chamber 14″ (shown atthe bottom of the figures) can contain the cathode 12 of primary directcathodic arc source or gaseous plasma source like hollow cathode orthermoionic cathode. The crucible of the metal vapor source 75 can beconnected to the positive or negative pole of the arc power supply 19 sothat it functions as a distributed arc plasma source in a FilteredE-Beam Heated Evaporated Anode (FEBHEA) mode or Filtered E-Beam HeatedEvaporated Cathode (FEBHEC) mode. That provides an ionized anodic arc orcathodic arc metal vapor flow which can be bent or deflected in acurvilinear magnetic field generated about the filtered arc source bydeflecting magnetic coils 20, outside the cusp of upstream focusingcoils 220 b, and subsequently focused by downstream focusing coils 220 atoward substrate chamber 10. That will eliminate any droplets,macro-particles and multi-atom clusters from the metal plasma flowinginto the plasma duct 16. In these Filtered E-Beam Heated EvaporatedElectrode (FEBHEE) embodiments two focusing magnetic coils 21 aredisposed on both sides of the bottom primary evaporation source chamber14 of the filtered arc source. The evaporation material has to be placedin the vicinity of the plane of symmetry between two focusing coils 21.If evaporation source used in this embodiment is electron beam sourcethe electron beam position should be restricted to the area of themagnetic field cusp of the focusing coils 21, where the intensity of thefocusing magnetic field is near zero. Two additional side coils 41 canbe optionally used for correction the position of the electron beam whendeflecting coils of the filtered arc source are activated.

[0132] It should be noted that a sputter deposition plasma source suchas a magnetron can also be installed in a cathode chamber 75 instead ofthe primary cathodic arc source or metal vapor source with heatedevaporated electrode. In this case a sputtering gas such as argon has tobe added to gaseous plasma environment for sputtering the magnetrontarget. The sputtering gas is preferably injected into the chamber inthe vicinity of magnetron target. The preferable type of magnetronsputtering source used in this embodiment of the invention is anunbalanced magnetron, which can be coupled with the focusing coils ofthe primary plasma source of the filtered arc source.

[0133] In operation, the ionized metal vapor stream created by metalvapor source 75 flows along magnetic lines of the focusing magneticfield created by focusing coils 21 toward entrance of the plasma duct16. In the vicinity of the entrance of plasma duct 16 the focusingmagnetic field created by the coils 21 is overlapped by the deflectingmagnetic field of the deflecting coils 20. In this area the metal vaporplasma will be turned along magnetic field lines of the deflectingmagnetic coils 20 toward the substrate chamber 10. The electrostaticfield created between deflecting electrode 30 and grounded walls of theplasma duct 16 (and further between the repelling electrode 60 and afocusing electrode 23 if provided, not shown in FIG. 8m or 8 n), willfocus the metal ion plasma flow toward substrates 4 to be coated. Theoptional opposite plasma flow created by the primary plasma source 12contained in the opposite cathode chamber 14″ of the filtered arc sourcewill merge with bottom metal vapor plasma at the exit of the plasma duct16 in front of the substrate platform 2 in the substrate chamber 10,downstream of the repelling electrode 60.

[0134] In operation of the sputter deposition magnetron source, asputter gas such as argon is injected in the vicinity of magnetrontarget to a partial pressure typically ranging from 5×10⁻⁴ to 5×10⁻³Torr. The DC or AC voltage is applied to the magnetron target to startsputtering of the target material. The sputter flux will be partiallyionized by the magnetron and/or cathodic arc plasma, and trapped by thefocusing and deflecting magnetic fields of the plasma duct. Diffusion ofionized metal vapor or sputter metal-gaseous plasma in the directiontransversal to the magnetic force lines in a plasma guide is given by

[0135] where D is diffusion coefficient of metal vapor or sputter plasmain the absence of a magnetic field; n is a parameter ranging from 1 to2. Equation (5) shows that diffusion flow of metal vapor or sputterplasma in the plasma duct along the magnetic force lines exceeds thediffusion flux in the direction transversal to the magnetic force lines(i.e. toward the walls of the plasma duct) by a factor of B^(n). Thiscan be used for estimating the effectiveness of transporting of metalvapor or sputter plasma along the curvilinear magnetic field created bythe focusing and deflecting magnetic coils 21 of the filtered arc plasmaduct.

[0136] In another preferred embodiment, illustrated in FIG. 9, thevacuum pumping system (not shown) is in communication with the interiorof the apparatus behind the deflecting electrode 50. In this embodimenta “getter pump” effect is achieved by the constant bombardment of thedeflecting electrode 50 with ions such as titanium and zirconium. Thedeflecting electrode 50 in this embodiment acts as a “vacuum arc plasmatrap” which both increases the pumping speed and diverts metal ions fromthe plasma flow toward the coating chamber 42. This effect can beenhanced by applying a negative or floating potential to a shroud 52surrounding the deflecting electrode 50, which provides a negativepotential in the vicinity of the deflecting electrode that more readilyattracts ions and thus increases ion bombardment of the shroud 52, whichthus acts as a gettering surface. Preferably the shroud 52 is formedfrom a stainless steel mesh with large openings (e.g. one to threecentimetres), and the surface area of the mesh can be maximized (tomaximize ion attraction) by providing conductive ribs or platesextending orthogonally relative to the deflecting electrode plate 50 a.The deflecting electrode 50 in this embodiment should be regularlyremoved and cleaned of contaminants and accumulated debris.

[0137] This embodiment provides the additional advantage of reducingbackstreaming of diffusion pump oil vapours, represented by undulatingarrows in FIG. 9, into the apparatus 40. Oil molecules tend to initiallyadhere to the deflecting electrode 50 and are quickly trapped by acoating of metal film that forms on the deflecting electrode 50 throughion bombardment.

[0138] FIGS. 4 to 7 illustrate a multiple cathode-pair embodiment of theinvention utilizing a conventional vacuum pumping system 8. As best seenin FIG. 5, a plurality of pairs of cathode chambers 44 are disposed instacked relation on either side of a long vertical plasma duct 46. Asshown in FIG. 4, the stack of cathode chamber pairs on each side of theplasma duct 46 is hinged to the apparatus to allow access to the plasmaduct and the coating chamber 42.

[0139] As noted above, the use of linear deflecting and focusingconductors 20 a, 21 allows the plasma duct to be of virtually unlimitedlength. A plurality of positively biased repelling electrodes 60 aredisposed axially along the plasma duct 46. The apparatus of FIGS. 4 to 7operates as described above in relation to the dual cathode embodimentof FIG. 3b, driving the plasma flow through a common plasma duct 46toward a common coating chamber 42.

[0140] To compensate for the non-uniform plasma density, particularly inthe case of a non-rectangular plasma source 12, isolating coils 58 aredisposed about the interior of the plasma duct 46. These isolating coils58 are isolated from the plasma flow, preferably by a water coolingenclosure and shielded by medial auxiliary anodes 67, and divide theplasma duct into magnetically isolated sections or “cells”. Theisolating coils 58 can be rastered in sequence in opposite directions(boustrophedonically) to render the plasma stream more uniform as ittraverses the plasma duct 46. By imposing a vertically scanning magneticfield in alternating directions using the isolating coils 58, the plasmastream is stabilized and dispersed uniformly within the plasma duct 46.FIG. 12 illustrates coating thickness as a function of distance from thetop of the apparatus in an alternating vertical scanning embodiment ofthe invention.

[0141] The embodiment of FIGS. 4 to 7 thus permits a common plasma duct46 to be of virtually unlimited length, since the isolating coils createseparate cells within which the plasma is uniformly distributed, and canbe rastered to assist in driving the plasma flow through the elongatedplasma duct 46 to the coating chamber 42.

[0142] The plasma jet is driven through the plasma guide 46 with ahelical rotation, the direction of rotation being determined by thedirection of the magnetic fields generated by the deflecting coils 20and focusing coils 21 (and steering and focusing coils of the cathodicarc sources). The helical rotation of the plasma jet causes ions toimpact the substrates 4 at an angle, creating an “ion shadow” on thesubstrates. Periodically changing the direction of all deflecting andfocusing magnetic fields in the plasma duct 46 (as well as steering andfocusing coils of the cathodic arc sources) similarly changes thedirection of helical rotation of the plasma flow, and by allowing ionsto bombard the substrates from different angles thus generates a moreuniform coating structure, particularly in multi-layer coatings.

[0143]FIG. 5b illustrates a variant of this embodiment in which impulsecathodic arc sources 22 are provided, to allowing for rastering orscanning of the cathodic arc sources 22 in conjunction with theisolating coils 58 during the coating process. When the impulse cathodicarc sources 22 are energized, plasma jets are generated in bursts alongmagnetic field lines created by the deflecting magnetic coils 20 and arastering system established by scanning the isolating coils 58. Thesemagnetic coils 20, 58 combine to create a magnetic field “wave” whichguides the plasma jets toward the coating chamber 42. By rastering themagnetic fields in conjunction with impulsing of the cathodic arcsources 22, each impulse provides a burst of metal plasma to a differentlocation along the substrates 4. In order to ensure a uniform coating,the rastering cycle for the impulse cathodes 22 should be much shorter,for example 10 times shorter, than the scanning cycle for the isolatingcoils 58.

[0144]FIG. 5c illustrates a still further variation of the embodiment ofFIG. 5b, in which impulse lasers 360 have been used to ignite impulsevacuum arc discharge on the surface of cathode target 12. The energyaccumulated in the capacitors 321 will be released and transformed intokinetic energy of the ablation plasma jet 346 created by interaction ofthe impulse laser beam 361 with the surface of cathode target 12. Theresulting target material plasma stream will be deflected in thecurvilinear magnetic field of the filtered arc plasma duct 44,containing the deflecting anode 350 (grounded) with baffles 350 afollowed by interaction with repelling anode 60 which results in theformation of an ion plasma stream toward substrates 4 to be coated. Incase of impulse laser plasma ablation, a non-conductive material likesilicon or boron or alumina can be used as a cathode target 12. In thiscase the power supply 26 a can be installed between the repelling anode60 (positive pole) and ground (negative pole).

[0145] In all of the described embodiments the filtered arc source canbe any kind of plasma source, including hollow cathode plasma sources,and magnetoplasmadynamic accelerators providing a supersonic plasma jetthroughout the apparatus. In impulse cathodic arc sources, and any otherplasma jet sources, in order for the plasma jet to retain its integritythe directed kinetic energy of the ion component of the plasma mustexceed the chaotic average kinetic energy of the electron component ofthe plasma (i.e. the electron temperature), which can be described asE_(i)>>κ*T_(e) in which E_(i) is the directed kinetic energy of the ioncomponent in electron volts, T_(e) is the chaotic average kinetic energyof the electron component, and κ is Bolzmann's constant. Otherwise theion component will tend to diffuse into the plasma rather than flow in adirected plasma stream. Typically the chaotic kinetic energy of theelectron component is in the order of 1 to 5 electron volts, while theion component has a much smaller chaotic kinetic energy. In a filteredarc flow the directed kinetic energy of the ion component of the plasmais typically in the order of 20 to 200 electron volts. Another vaporplasma source having an average kinetic energy of emitted atomicparticles (evaporating or sputtering atoms/ions) which does not exceedthree times the chaotic average kinetic energy of the electron componentof the plasma (E_(i,a)<3κ*T_(e)) can be installed elsewhere in mainchamber 42 or in the plasma duct 46 in a position optically in sight ofthe substrate holder 2. This source can be a magnetron sputtering plasmasource, resistive evaporating plasma source and/or electron beamevaporating plasma source.

[0146]FIG. 12 shows an embodiment of the invention utilizing filteredarc sources with an additional filtration stage. In this embodiment thecathodes 12 are disposed in cathode chambers 44 in communication withfiltered plasma ducts 47 which are oriented substantially perpendicularto the optical axes of the cathodes 12, and which in turn are orientedsubstantially perpendicular to the main plasma duct 46. A repellingelectrode 60 is provided in the main plasma duct 46, and deflectingelectrodes 50 are positioned along the axis of the plasma duct 46 and atthe corners of the filtered plasma ducts 47 opposite the cathodes.Additional medial auxiliary anodes 49 may be provided near the junctionof the filtered plasma ducts 47 and the main plasma duct 46, to repelplasma from the apparatus walls. Deflecting conductors 20 are disposed,as in the previous embodiments, so that the magnetic cusps generatedthereby follow the plasma path from the cathodes 12 to the substrateholder 2. This embodiment, by orienting the main plasma duct 46 off ofthe axes of the filtered plasma ducts 47, provides the advantage of anadditional filtration stage which can be useful in semiconductor andoptical applications, where a particularly clean plasma is required.

[0147] Following are examples of the treatment of substrates in theembodiments described above:

EXAMPLE 1 Filtered Arc Plasma Immersed Ion Cleaning

[0148] The arc coating apparatus shown in FIG. 3b was used in thisprocess. The apparatus was equipped with two dual-filtered arc sources,having round cathodes 12 measuring 3″ in diameter and 2″ in height, onefiltered arc source having titanium targets and the other havingchromium targets. The exit opening of the filtered arc sources wasequipped with load lock shutters 80 a, 80 b, electron-permeable toprovide a free passage of electron current from the cathode targets 12to distal auxiliary anodes 70 to thereby establish an auxiliary arcdischarge. Augmented by the auxiliary arc discharge the ionization andactivation of the gaseous component of the plasma environment in thecoating chamber 42 was significantly increased (up to 30 to 40% incomparison with approximately 1 to 3% gas ionization rate without theauxiliary arc discharge).

[0149] 2″ diameter, ¼″ thick HSS disc coupons as substrates 4 werewashed in a detergent containing a water solution and dry by isopropylalcohol and placed in a dry cabinet for 2 hours at 200° C. Thesubstrates 4 were then loaded into the coating chamber 42 and attachedto the rotary satellites of the substrate platform 2, for doublerotation at a rotational speed of 12 rpm. The vacuum chamber wasevacuated to 4×10⁻⁶ Torr and then a gas mixture containing 80% argon,18% hydrogen and 2% oxygen as an ion cleaning gas, was injected tocreate a total pressure ranging from 4×10⁻⁴ to 8×10⁻⁴ Torr. Both loadlock shutters 80 a, 80 b were locked and cathodic arc sources 12 wereactivated in at least one filtered arc source, preferably that with thetitanium targets. The deflecting magnetic system was not activated. Theauxiliary arc discharge was activated between the cathodes 12 of thefiltered arc source and the distal auxiliary anodes 70 installed in thecoating chamber 42. The total auxiliary discharge current wasestablished at 80 amps. The RF bias power supply was activated and aself-bias potential was established at 600 volts. The ion cleaning stagewas performed for 10 minutes.

EXAMPLE 2 Ion Nitriding and Ion Implantation in the Auxiliary ArcDischarge

[0150] The apparatus and substrate coupons 4 of Example 1 were used inthis process. After the ion cleaning stage the gas mixture was changedto nitrogen as an ion nitriding gas, injected to create a total pressureranging from 2×10⁻⁴ to 8×₁₀ ⁴ Torr. For ion nitriding the substrates 4were preliminary heated to 300° C. to 450° C. using conventional heaters(not shown) installed in front of the distal auxiliary anodes 70 in thecoating chamber 42. A self-bias voltage was established at a range from100 to 400 volts. The current applied to distal auxiliary anodes 70 wasset at 100 amps and the ion nitriding stage was performed for 1 hour.

[0151] For low-energy ion implantation the substrate temperature was setto a lower level, about 150 to 300° C., and the bias voltage ranged from200 to 3000 volts. The ion implantation stage was performed for 1 hour.

[0152] The ion nitriding and ion implanted layers were characterized bystructure, thickness, microhardness depth profile, and surfaceroughness. It was found that ion nitriding in this process provided agreater roughness of the substrate surface in comparison to ionimplantation, while the rate of nitriding was up to one order ofmagnitude greater than the rate of ion implantation. The rate of ionnitriding for HSS steel had reached up to 1 μm/hr in comparison with0.08 to 0.12 μm/hr for low energy ion implantation with the same 600volt self-bias on the substrates 4.

EXAMPLE 3 Auxiliary Arc Plasma Immersed Deposition of Chromium NitrideFiltered Arc PVD Coating

[0153] The apparatus of FIG. 3b was equipped with the same cathodetargets 12 as in Example 1. The same substrate coupons 4 as in Example 1were installed on the rotary satellites of substrate holder 2 withsingle rotation and preheated to 400° C. by conventional heatersinstalled in the coating chamber 42. After ion cleaning as described inExample 1 the lock load shutter 80 b of the filtered arc source with thechromium cathode targets 12 was opened and the gas was changed to purenitrogen with total pressure of 2×1⁻⁴ to 3×10⁻⁴ Torr. The deflecting andfocusing magnetic coils 13, 20 of the filtered arc source magneticsystems were activated to deflect the chromium plasma stream towardsubstrates. The total current of the deflecting anode 50 was establishedat 50 amps, and the total current of the repelling anode was establishedat 40 amps. The current between chromium cathodes 12 and distalauxiliary anodes 70 was established at 30 amps.

[0154] The load lock shutters 80 a corresponding to the other filteredarc source, with the titanium cathode targets 12, remained locked andthe corresponding deflecting coils 20 and deflecting anode 50 wereinactive while both cathodic arc sources with titanium targets 12 wereactivated. Without the deflecting em fields the plasma stream remainedsubstantially confined to the cathode chamber 44, and the titaniumcathode targets served as electron emitters, providing additionalcurrent to the distal auxiliary anodes 70 up to 80 amps. Coatingdeposition was performed for 3 hours. The nanohardness of the CrNcoatings was measured at a level of 22 to 25 GPa, in comparison to themicrohardness of regular CrN coatings prepared by direct vacuum arcdeposition process, which does not exceed 20 GPa.

EXAMPLE 4 Large Area TiN Filtered Arc Coatings

[0155] The apparatus of FIG. 3b was equipped with the same cathodetargets 12 as in Example 1. In this example the substrate coupons 4 weremade from stainless steel as bars with a 1″ width, ½″ thickness and 14″length. The substrates 4 were installed on the rotary satellitepositions of substrate platform 2, with double rotation. The substrates4 were preheated to 400° C. before the deposition stage commenced.

[0156] After ion cleaning the substrates 4 as described in Example 1, aTiN coating was deposited from the filtered arc source having titaniumcathode targets 12, while the other filtered arc source with chromiumcathode targets 12 was inactive. The current applied to the deflectinganode 50 was established at 60 amps, the current applied to therepelling anode 60 was established at 30 amps, and the current betweenthe titanium cathodes 12 and the distal auxiliary anodes 70 wasestablished at 30 amps to support and auxiliary arc-assisted filteredarc deposition process.

[0157] In the first trial the vertical magnetic field created byscanning isolating coils 58 (shown in FIGS. 5 to 7) was directed upward.In the second trial the vertical magnetic field created by scanningisolating coils 58 was directed downward. In the third trial theisolating coils 58 were activated in a periodically repeatable pulsemode with the magnetic field vector directed upward for 0.55 min and, inturn, the magnetic field vector directed downward for 0.45 min. Scanningthe isolating coils 58 in this fashion allowed up to a 90% uniformity ofcoating thickness over the large area coating zone (14″ in thisexample). By way of contrast, in a conventional direct cathodic arcdeposition process it is not possible to scan the plasma flow withelectromagnetic fields due to the neutral phase (atoms, clusters andmacroparticles) which constitute up to 60% of the total erosion mass ofthe vacuum arc jet.

EXAMPLE 5 Auxiliary Arc Plasma Immersed CVD Coatings

[0158] In this trial indexable carbide inserts, installed on the rotarysatellites of the substrate platform 2 with single rotation, were usedas substrate coupons 4. The process parameters were established as inExample 2, but in this case the gas mixture was provided asnitrogen+methane+titanium tetrachloride (TiCl₄) with total pressure ofabout 5×10⁻⁴ Torr. A bi-polar impulse bias voltage with an impulsefrequency of 250 kHz and a negative voltage of up to 600 volts wasapplied to the substrates 4 during this process. The highly activatedgaseous plasma environment resulted in a deposition rate for the TiCNcoating of up to 3 μm/hr in this low pressure plasma immersed CVDprocess.

EXAMPLE 6 Impulse Filtered Arc Deposition of Diamond-like Coatings (DLC)

[0159] In this example the apparatus of FIG. 5b was equipped withimpulse cathodic arc sources 12 having cylindrical targets made frompyrolitical graphite. Indexable carbide inserts as substrate coupons 4were installed on the satellites of substrate platform 2 with singlerotation at a rotational speed of 12 r.p.m. The apparatus was evacuatedto 5×10⁻⁶ Torr and DC bias voltage from DC bias power supply 29 b wasset to 1000 volts. The deflecting coils 13 and focusing coils 20 of thefiltered arc sources were activated. Deflecting anode 50 was connectedto the positive pole of DC power supply 29 a while a negative pole wasgrounded. The repelling anode 60 was connected to another DC powersupply 26 a in the same manner.

[0160] The isolating coils 58 were activated to provide verticalscanning with a periodic change in the direction of the verticalmagnetic field vector from up to down, with a repetition frequency of0.5 Hz. All impulse cathodic arc sources 12 were activated with a pulsedischarge repetition frequency of 10 Hz. During the first minute of theprocess, the bias voltage of the substrates 4 was established at to 1000volts to provide a sublayer between the carbide substrate surface andDLC film, while during deposition the substrate bias was reduced to 100volts. The rate of deposition of DLC over a 12″ high and 20″ diametercoating zone reached 1 μm/hr. The nanohardness of DLC created in thisprocess reached up to 65 Gpa.

EXAMPLE 7 Impulse Filtered Arc Implantation of Titanium in H13 Steel

[0161] In this example the apparatus of Example 6 was used. The impulsecathodic arc sources 12 were equipped with titanium targets as centralelectrodes. All other parameters of the process were set up as inExample 6, but the DC bias on the substrates 4 was established at 3000volts. In this case the duration of the coating process was 2 hours,resulting in titanium implantation of the H13 steel coupons with depthabout 1 μm.

EXAMPLE 8 Large Area Plasma Immersed Hybrid Filtered Arc/MagnetronTiCrN/CrN Multi-layer Coatings

[0162] In this example substrate coupons 4 were ½″×½″ indexable carbide(WC-6% Co) inserts, installed on the satellite positions of thesubstrate platform 2 with double rotation and vertically distributedevenly over a 14″ vertical deposition zone. The coating chamber 4 layoutused for this experiment is shown schematically in FIG. 8c. Two titaniumcathode targets 12 were installed on the dual-arc filtered arc source,while both magnetron sources 90 were provided with chromium targets. Thesubstrates 4 were preheated to 400° C. before the deposition stagecommenced.

[0163] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and a Ti coating wasdeposited from the dual arc filtered arc source for a duration of 3minutes. Pure argon as a plasma-creating gas was injected in thevicinity of the magnetron targets 90 to a total operating pressure 2×10′to 4×10′ Torr. The substrate bias voltage during deposition of the Tisublayer was held at 600 V, providing extensive ion bombardment of thesubstrates 4 before the deposition of the main layers. The total currentof the auxiliary arc discharge (between the titanium cathodes 12 of thefiltered arc source and the distal auxiliary anodes 70 surrounding themagnetron cathodes 90) was set at 100 amps.

[0164] After 3 minutes of Ti coating deposition nitrogen was added togas mixture, to provide a reactive gaseous component of gas-metal plasmafor the deposition of TiCrN coatings. Both magnetrons 90 were activatedwith the magnetron cathode 90 voltage set at 650 volts. The currentapplied to the deflecting anode 50 was established at 60 amps, and thecurrent applied to the repelling anode 60 was established at 30 amps.When the deflecting magnetic field of the filtered arc source wasactivated, a TiCrN layer was deposited on the substrates 4 for aduration of 10 minutes. This was followed by a CrN layer depositionstage lasting 30 minutes, during which the deflecting magnetic field ofthe filtered arc source was deactivated, but the auxiliary arc dischargeremained established between the arc cathodes 12 of the filtered arcsource and the auxiliary anodes 70, providing a greater ionization ratefor the gaseous plasma component. The result was both higherproductivity of magnetron sputtering and a fine CrN coating structure.

EXAMPLE 9 Large Area Filtered Arc Plasma Immersion Ion Vapor Depositionof Corrosion Resistant Platinum Coating for Fuel Cell Plates

[0165] In this example substrate proton exchange membrane fuel cell(PEMFC) endplates 6″ in diameter made of aluminum with a 75 μmphosphorous-nickel electroplating coating, were installed on thesatellite positions of the substrate platform 2 with double rotation andhorizontally distributed evenly over a 14″ long deposition zone. Thecoating chamber 4 layout used for this experiment is shown schematicallyin FIG. 8d. Two titanium cathode targets 12 were installed on thedual-arc filtered arc source, while a crucible 70 a in a form of DCheated tungsten foil boat was provided with 150 mg of 99.95% pureplatinum. The substrates endplates were preheated to 300 degrees C.before the deposition stage commenced.

[0166] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and a Ti coating wasdeposited from the dual arc filtered arc source for a duration of 1hour. Pure argon as a plasma-creating gas was injected into the mainchamber 42 to a total operating pressure of 2×10⁻⁴ to 4×10⁻⁴ Torr. Thesubstrate bias voltage during deposition of the Ti interlayer was heldat −60 V, providing extensive ion bombardment of the substrates beforethe deposition of the main layers. The total current of the auxiliaryarc discharge (between the titanium cathodes 12 of the filtered arcsource and the distal auxiliary anode 70) was set at 100 amps.

[0167] After 1 hour of Ti coating deposition the tungsten boat washeated by DC resistant heating to 1800 degrees C. for evaporatingplatinum. The deflecting magnetic system was deactivated and platinumcoating was deposited over an interval of 2 hours. The result was ahighly adhesive platinum corrosive resistant coating having 20 nmthickness, providing stable operation of the endplates in a highlycorrosive PEMFC environment. The distribution of electrical resistivityover the surface of the endplates was measured by a 4-points probe,showing a uniformity of surface electrical resistance at +/−5% over thesurface of PEMFC endplates. This distribution was not changed afterexposing the endplates to a PEMFC water environment over 350 hrs.

EXAMPLE 10 Large Area Filtered Arc Plasma Immersion Ion Vapor Depositionof Corrosion Resistant Platinum Coating having Me/MeN Buffer MultilayerIntermediate Coating for Fuel Cell Plates

[0168] In this example substrate proton exchange membrane fuel cell(PEMFC) endplates 6″ in diameter were made of aluminum by a stampingprocess followed by 75 μm phosphorus nickel electroplating coatings. Theplates to be coated were installed on the satellite positions of thesubstrate platform 2 with double rotation and horizontally distributedevenly over a 14″ long deposition zone. The coating chamber 4 layoutused for this experiment is shown schematically in FIG. 8i. Differentpairs of cathode targets 12 were installed on the opposite primarycathodic arc sources of the dual-arc filtered arc source, as is shown inTable 1, while the crucible 70 a in a form of DC heated tungsten foilboat was provided with 150 mg of 99.95% pure platinum. The substrateendplates were preheated to 300 degrees C. before the deposition stagecommenced. TABLE 1 Type of cathode targets for multilayer cermetcoatings Item # Left Target Right Target Multilayer Coating 1 Ti TiTi/TiN 2 Ti Cr TiCr/TiCrN 3 Cr Cr Cr/CrN 4 Zr Zr Zr/ZrN 5 Ti ZrTiZr/TiZrN

[0169] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and a TiN/ZrNsuperlattice coating was deposited from the dual arc filtered arc sourcefor a duration of 3 hrs to achieve coating thickness of about 3 μm. Purenitrogen as a plasma-creating gas was injected into the main chamber 42to a total operating pressure of 2×10⁻⁴ to 4×10⁻⁴ Torr. The substratebias voltage during deposition of the TiN/ZrN interlayer was held at −40V, providing extensive ion bombardment of the substrates before thedeposition of the main layers. The total current of the auxiliary arcdischarge between the titanium and zirconium cathodes 12 of the filteredarc source and the distal auxiliary anodes 70 and REHA-crucible 70 a wasset at 100 amps.

[0170] After 3 hours of TiN/ZrN coating deposition the tungsten boat washeated by DC resistant heating to 1800 degrees C. for evaporatingplatinum. Deflecting magnetic system was deactivated and a platinumcoating was deposited over an interval of 2 hrs. The result was a highlyadhesive platinum corrosive resistant coating having a 25 nm thicknessover superlattice TiN/ZrN 3 μm coating, providing stable operation ofthe endplates in highly corrosive PEMFC environment. The distribution ofelectrical resistivity over the surface of endplates was measured by4-points probe, showing a uniformity of the surface electricalresistance of +/−5% over the surface of the PEMFC endplates. Thisdistribution was not changed after exposing the endplates to a PEMFCwater environment over 350 hrs.

EXAMPLE 11 Large Area Filtered Arc Plasma Immersion Ion Vapor Depositionof Corrosion Resistant Platinum Coating with TiN/ZrN Superlattice BufferInterlayer for Fuel Cell Plates

[0171] In this example substrate proton exchange membrane fuel cell(PEMFC) endplates 6″ in diameter were made of aluminum by a stampingprocess followed by 70 μm phosphorus nickel electroplating coatings. Theplates to be coated were installed on the satellite positions of thesubstrate platform 2 with double rotation and horizontally distributedevenly over a 14″ long deposition zone. The coating chamber 4 layoutused for this experiment is shown schematically in FIG. 8i. Onezirconium and one titanium cathode target 12 was installed opposite theprimary cathodic arc sources of the dual-arc filtered arc source, whilethe crucible 70 a in a form of DC heated tungsten foil boat was providedwith 150 mg of 99.95% pure platinum. The substrate endplates werepreheated to 300 degrees C. before the deposition stage commenced.

[0172] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and a TiN/ZrNsuperlattice coating was deposited from the dual arc filtered arc sourcefor a duration of 3 hours to achieve a coating thickness of about 3 μm.Pure nitrogen as a plasma-creating gas was injected into the mainchamber 42 to a total operating pressure of 2×10⁻⁴ to 4×10⁻⁴ Torr. Thesubstrate bias voltage during deposition of the TiN/ZrN interlayer washeld at −40 V, providing extensive ion bombardment of the substratesbefore the deposition of the main layers. The total current of theauxiliary arc discharge between the titanium and zirconium cathodes 12of the filtered arc source and the distal auxiliary anodes 70 andREHA-crucible 70 a was set at 100 amps.

[0173] After 3 hrs of TiN/ZrN coating deposition the tungsten boat washeated by DC resistant heating to 1800 degrees C. for evaporatingplatinum. Deflecting magnetic system was deactivated and a platinumcoating was deposited over an interval of 2 hours. The result was highlyadhesive platinum corrosive resistant coating having 20 nm thicknessover a superlattice TiN/ZrN 3 μm coating, providing stable operation ofthe endplates in highly corrosive PEMFC environment. The distribution ofelectrical resistivity over the surface of endplates was measured by a4-points probe, showing uniformity of the surface electrical resistanceat +/−5% over the surface of PEMFC endplates. This distribution was notchanged after exposing the endplates to a PEMFC water environment over350 hrs.

EXAMPLE 12 Large Area Filtered Arc Plasma Immersion Ion Vapor Depositionof Corrosion Resistant Palladium Coating for Fuel Cell Plates

[0174] In this example substrate PEMFC endplates 6″ in diameter made oftitanium, were installed on the satellite positions of the substrateplatform 2 with double rotation and horizontally distributed evenly overa 14″ long deposition zone. The coating chamber 4 layout used for thisexperiment is shown schematically in FIG. 8e. Two titanium cathodetargets 12 were installed on the dual-arc filtered arc source, while thecrucible 70 a in a form of an indirect resistance heated aluminacrucible was provided with 300 mg of 99.95% pure palladium. Thesubstrate endplates were preheated to 300 degrees C. before thedeposition stage commenced.

[0175] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and a Ti coating wasdeposited from the dual arc filtered arc source for a duration of 1hour. Pure argon as a plasma-creating gas was injected in the mainchamber 42 to a total operating pressure of 2×10⁻⁴ to 4×10⁻⁴ Torr. Thesubstrate bias voltage during deposition of the Ti interlayer was heldat −40 V, providing extensive ion bombardment of the substrates beforethe deposition of the main layers. The total current of the auxiliaryarc discharge (between the titanium cathodes 12 of the filtered arcsource and the distal auxiliary anode 70) was set at 100 amps.

[0176] After 1 hr of Ti coating deposition the crucible was heated by DCresistant heating to 1600 degrees C. for evaporating palladium. Thedeflecting magnetic system was deactivated and a platinum coating wasdeposited over an interval of 1 hour. The result was highly adhesivepalladium corrosive resistant coating having 60 nm thickness, providingstable operation of the endplates in a highly corrosive proton exchangemembrane fuel cell environment. The distribution of electricalresistivity over the surface of the endplates was measured by 4-pointsprobe, showing a uniformity of the surface electrical resistance at+/−2% over the surface of the PEMFC endplates. This distribution was notchanged after exposing the endplates to a PEMFC water environment over350 hours.

EXAMPLE 13 Large Area Filtered Arc Plasma Immersion Ion Vapor Depositionof Corrosion Resistant Coating for Fasteners

[0177] In this example sample the substrates were fasteners such as nutsand washers made of austenitic stainless steel. The coating chamber 4layout used for this experiment is shown schematically in FIG. 8h. Thesubstrates were installed on the satellite positions of the substrateplatform 2 with double rotation and horizontally distributed evenly overa 14″ long deposition zone. Two molybdenum cathode targets 12 wereinstalled on the dual-arc filtered arc source, while the crucible 70 ain a form of a resistance heated graphite crucible was provided with 100g of 99.9% aluminum. The substrates fasteners were preheated to 300degrees C. before the deposition stage commenced.

[0178] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and an Mo interlayercoating was deposited from the dual arc filtered arc source for aduration of 10 minutes. Pure argon as a plasmacreating gas was injectedinto the main chamber 42 to a total operating pressure of 2×10⁻⁴ to4×10⁻⁴ Torr. The substrate bias voltage during deposition of the Mointerlayer was held at −200 V, providing extensive ion bombardment ofthe substrates before the deposition of the main layer. The totalcurrent of the auxiliary arc discharge (between the Mo cathodes 12 ofthe filtered arc source and the distal auxiliary anode 70) was set at100 amps.

[0179] After 10 minutes of Mo coating deposition the graphite cruciblewas heated by DC resistant heating to 1100 degrees C. for evaporatingaluminium. Deflecting magnetic system was activated providingsimultaneously Mo filtered cathodic arc plasma flow and aluminium anodicarc vapor plasma stream toward the substrates to be coated. The Al/Mocoating was deposited over an interval of 3 hours. The result was ahighly adhesive aluminium coating alloyed with molybdenum having 20 μmthickness. Corrosion resistance test provided in neutral salt spraydemonstrated no sign of corrosion over 350 hours.

EXAMPLE 14 Large Area Filtered Arc Plasma Immersion E-Beam Deposition ofcubic Boron Nitride coatings.

[0180] In this example sample substrates were indexable carbide insertsof the same size as in Example 8. The coating chamber 4 layout used forthis experiment is shown schematically in FIG. 8h. The substrates wereinstalled on the substrate platform 2 and horizontally distributedevenly over a 14″ long deposition zone. Two cathode targets 12 made ofboron carbide (B₄C) were installed on the dual-arc filtered arc source,while the crucible of the electron-beam evaporator was provided with 50g of 99.95% pure compacted boron powder. The substrate inserts werepreheated to 300 degrees C. before the deposition stage commenced.

[0181] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and a boron carbideinterlayer coating was deposited from the dual arc filtered arc sourcefor a duration of 20 minutes. Pure argon as a plasma-creating gas wasinjected into the main chamber 42 to a total operating pressure rangingfrom 2×10⁻⁴ to 4×10⁻⁴ Torr. The substrate bias voltage during depositionof the boron carbide interlayer was held at −40 V, providing extensiveion bombardment of the substrates before the deposition of the mainlayer. The total current of the auxiliary arc discharge (between theboron carbide cathodes 12 of the filtered arc source and the distalauxiliary anode 70) was set at 120 amps.

[0182] After 10 minutes of boron carbide coating deposition the argonwas replaced by nitrogen as reactive gas to deposit the following boroncarbo-nitride BCN interlayer coating over 20 minutes. After this stagethe electron-beam gun was activated to start boron evaporation. Theboron vapor plasma stream was merged with the boron-carbon filtered arcplasma stream for deposition BCN coating with excess boron concentrationover 10 minutes. After this stage the deflecting magnetic system of thefiltered arc source was deactivated and a boron nitride coating wasdeposited during an interval of 30 minutes from boron vapor plasmacreated by the electron beam evaporation of boron in a highly ionizedauxiliary arc plasma created between the cathodes of the filtered arcsource and distal anode 70. The result was highly adhesive boron nitridecoating consisting of more than 80% of a cubic BN phase, as measured byIR absorption spectroscopy.

EXAMPLE 15 Large Area Filtered Arc Plasma Source Ion Deposition ofInterfacial Coating for Thermal Barrier Coating System

[0183] Thermal barrier coatings (TBC) are currently used to protectengine components from thermal stress. To promote adhesion and extendthe service life of a TBC system, an oxidation-resistant bond coat isoften employed. Bond coats are typically in the form of overlay coatingssuch as MCrAlX (where M is iron, cobalt and/or nickel, and X is yttriumor another rare earth element), or diffusion aluminide coatings. Anotable example of a diffusion aluminide bond coat contains platinumaluminide (Ni(Pt)Al) intermetallic.

[0184] Contemporary TBCs comprise a complex multi-layer metal-ceramicarchitecture. The basic architecture of TBC typically consists of aMeCrAlY overlay or aluminide Ni(Pt)AI intermetallic bond coat followingby a thick yttria stabilized zirconia (YSZ) base ceramic thermalinsulation layer. The temperature on the surface of the TBC can reach upto 1600° C., decreasing to the level of 1100-1200° C. in thebond-coating layer. The critical area, which determines the longevity ofthe TBC and consequently the durability of the blades and vanes, is theboundary between the intermetallic bond coating and top thermalinsulation ceramic layer. Significant improvement in bond coatingperformance can be achieved by introducing a nanostructured multi-layerand functionally graded architecture of bond layer-to-ceramic TBC layerinterface. It was also found that incorporating oxide inclusions in thebond coat layer will allow it to reduce the velocity of growth of thealumina scale layer and therefore increase the durability of TBC coatingsystem. Co-depositing zirconia as second-phase dispersion in the aluminacoating allow to refine alumina grain size and improve the fracturetoughness of the coating.

[0185] Multi-layer and functionally graded coating architecture is knownas an effective way to increase the probability of micro-cracks beingarrested in a coating and preventing crack propagation toward thesubstrate. Multi-layer and nanostructured coatings demonstrate improvedcrack resistance and allow control of the thermal and intrinsic stressesin coatings. Incorporating a stable oxide interlayer in a bond coatingallow further reduction of the inter-diffusion in thebondcoat-to-alumina interface and subsequently reduce the rate ofthermally grown oxide scale that causes thermal fatigue of the coatedarticles. Multi-layer structure of transition bond coating/alumina zoneas well as modified α-alumina scale can reduce the rate of TGO in a hightemperature oxidized environment. In a further advance of theinterfacial coating the modified α-alumina layer can be encapsulated by5 to 10 μm thick YSZ/alumina nano-structured multi-layer coating whichcan be deposited on top of the alumina scale by filtered arc plasmaimmersion e-beam evaporation of YSZ. The composite coating reduces heattransfer to the substrate, thereby reducing deformation-related crackingof the coating. It also minimizes grain growth during high-temperaturedeposition and exposure.

[0186] The anticipated coating architecture is shown in FIG. 13. Itconsists of multi-layer MeCrAIY/alumina bondcoat-to-α-alumina interface,optionally doped with platinum (5-10 μm), modified fine grain α-aluminainterlayer 0.5-1.5 μm thick optionally doped with yttria, zirconia orchromia followed by alumina-to-topcoat interface (5-10 μm) havingnano-structured multi-layer alumina/zirconia, or alumina/YSZarchitecture.

[0187] The operating pressure range for different plasma processingtechnologies is represented in FIG. 14. It can be seen that filteredvacuum arc plasma can operate over a wide pressure range, from about 5mTorr to about 10⁻⁶ Torr, overlapping most vacuum PVD processes.Schematic illustration of the filtered arc plasma source ion deposition(FAPSID) universal surface engineering system, used for deposition ofthe interfacial bondcoat-to-topcoat multilayer coating, is shownschematically in FIGS. 8k and 8 l. This system is equipped with twolarge area dual filtered arc sources, two unbalanced magnetrons (25 kWea.), two e-beam evaporators (6 kW ea.) and DC thermal resistanceevaporation source. It has a rotatable substrate holder assembly 2connected to a DC pulse bias power supply. The substrate chamber 10 isalso equipped with optical emission plasma diagnostic equipment, whichallows the operator to monitor in situ the intensity of optical emissionradiation of atomic particles during the coating deposition process. Aspectral-optical thickness monitor enables in situ measurement of EB-PVDdielectric coating thickness. This system is also equipped withelectrostatic Langmuer probes and ion collector probes to measuredistribution of plasma ion current density in the highly ionizedfiltered arc immersion plasma environment. Position of electron beams ofE-beam evaporators is monitored by miniature video cameras.

[0188] A foil or thin sheet metal specimen made of NiCrAlY alloy wasused to characterize deposition rate and coating thickness uniformity.Substrate temperature during deposition of an α-alumina interlayerranged from 900° C. to 1200° C. To provide adequate heating capabilitiesof substrate to be coated the built-in substrate heater is employedincorporated into the rotating substrate holder platform 2 and connectedto the heater power supply by powerful sliding contacts having protectshields against short circuits in the metal vapor plasma environment(FIGS. 8k and 8 l). The substrate foil strip specimen 4, or coupon, wasinstalled on the rotating substrate holder 2, which was connected toboth the bias power supply and to the DC current power supply for directcurrent resistance heating of the foil. The powerful high current feedsthrough the graphite/copper-based sliding electrical contacts. This wasused to supply heating current to the rotating foil specimen as shownschematically in FIGS. 8k and 8 l. The foil temperature was calibratedprior to plasma processing under ultimate vacuum conditions by means ofan optical pyrometer. The target material distribution over differentdeposition sources as well as characteristic parameters of the coatingdeposition process is presented in Table 1 below: TABLE 1 Characteristicparameters for deposition multi-layer interfacial coating for TBCcoating system in FAPSID system shown in FIG. 8k,1. Operating Plasmapressure, Current, sources Target material mTorr amperes Voltage, voltsLAFAS One target - 99.99% 8 mTorr-0.1 mTorr Total arc 40-60 volts (largearea aluminum; another current 300 filtered arc (opposite) targetamperes; ion source) aluminum/6% Si current output  ˜6 amperesUnbalanced NiCrAlY alloy   3-0.5 mTorr  30 amperes 800 volts arcassisted magnetron EB- One crucible is filled 0.5-0.05 mTorr   0.5amperes 10000 volts evaporator with carborundum and another one filledwith YSZ as evaporated material DC Platinum   3-0.05 mTorr ˜200 amperes10-20 volts resistance evaporator Auxiliary   1-0.1 mTorr ˜100 amperes90 volts arc source

[0189] For deposition of the NiCrAlY/alumina (Pt) multi-layer segmentlayer of the interfacial bondcoat-to-topcoat coating the arc enhancedunbalanced magnetron sputtering of NiCrAlY in co-deposition mode withaluminum filtered arc plasma deposition was used. The argon operatingpressure during magnetron deposition was set at 1 mTorr. A filtered arcsource was used to generate the flow of 100% ionized aluminum plasmacoinciding with magnetron sputtering. A small dope of silica wasprovided by an Al/6% Si target of the filtered arc source. The cycle ofdepositing the NiCrAlY sub-layer was followed by depositing anultra-thin alumina layer by the filtered arc source with aluminumtargets operating in oxygen-reactive gaseous plasma environment withoperating oxygen pressure 0.2-0.4 mTorr. The magnetron source was turnedoff during deposition of the alumina interlayers. The time of depositionof the NiCrAlY sub-layers was 10′ while for the alumina interlayers itwas 2′. The thermal resistance evaporation of platinum as a dope toalumina was used continuously in conjunction with a magnetron/filteredarc coating deposition process.

[0190] Deposition of about 5 μm thick multi-layer NiCrAIY/aluminasegment layer was followed by deposition of 1.5 μm α-alumina diffusionbarrier interlayer coating. Co-deposition of α-alumina by evaporation ofcarborundum by E-beam evaporator was used as a seed (template) dope toenhance formation of the α phase in polycrystalline alumina layer. Theα-alumina interlayer was encapsulated by alumina/zirconia multi-layertop coating segment by using co-deposition of alternative layers ofalumina and zirconia by E-beam evaporators with alumina and zirconiaevaporation material in conjunction with filtered arc deposition ofalumina in an oxygen-reactive atmosphere. Oxygen pressure duringfiltered arc immersion E-beam evaporation of oxide coatings was set at0.1-0.2 mTorr.

[0191] The structure and morphology of the interfacial coating wereexamined by SEM as well as metallurgical micro-cross-sectional analysis.The resulting interfacial multi-layer coating appeared to be uniform,pin-hole free and stable in an oxidizing atmosphere up to 1200 deg C.

EXAMPLE 15 Deposition of DLC coating by FEBHEA

[0192] In this example the apparatus of FIG. 8n was used for depositioncarbon DLC coatings by Filtered E-Beam Heated Evaporated Anode (FEBHEA).Pyrolitical graphite as an evaporating material (HEA target) was placedin a crucible of the FEBHEA plasma source 75. Indexable carbide insertsas substrate coupons 4 were installed on the platform 2 with singlerotation at a rotational speed of 12 r.p.m. The apparatus was evacuatedto 5×10⁻⁶ Torr. The deflecting coils 20 and focusing coils 21 of thefiltered arc sources were activated. Deflecting anode 50 was connectedto the positive pole of a DC power supply while a negative pole wasconnected to the thermoionic cathode 12. The repelling anode 60 wasconnected to another DC power supply in the same manner. The focusingcoils 21 were activated to establish a magnetic cusp surrounding theE-Beam evaporator 75, such that the electron beam from the electron beamevaporator was positioned in the area where the magnitude of thefocusing magnetic field approached 0. The anodic arc current between thethermoionic cathode 12 and HEA crucible 75 was set at 240 amperes. A13.56 MHz/5 kW RF generator with matching network was used as a biaspower supply (not shown in the FIG. 8n) for a DLC coating depositionprocess. During the first 20s of the process, the autopolarization biasvoltage of the substrates 4 was established at 1000 volts to provide asublayer between the carbide substrate surface and the DLC film, whileduring deposition the substrate bias was reduced to 100 volts. Theresidual gas pressure during DLC deposition was held at 0.01 mTorr. Therate of deposition of DLC over a 6″ high and 20″ diameter coating zonereached 0.5 μm/hr. The micro-hardness of DLC created in this processreached up to 35 Gpa.

EXAMPLE 16 High Temperature Conductive CrN/CrAl(Si)N Nano-structuredMultilayer Coating with Lanthanum Chromate Top Layer for Solid OxideFuel Cell (SOFC) Interconnect Plates.

[0193] In this example the substrate simulating the SOFC interconnectplates was a thin sheet strip specimen 4 cm×1 sm×0.025 cm in size madeof 304 Stainless Steel having surface roughness R_(a)<20 nm. The coatingchamber 4 layout used for this experiment is shown schematically inFIGS. 8k and l. The substrate thin sheet strip specimen, or coupon, wasinstalled on the rotating substrate holder by single rotation fixture,to which was connected the bias power supply (as shown in FIGS. 8k and1). The substrate was heated by conventional radiation heaters installedin the coating chamber 4. One chromium target and one aluminum/6% Sicathode target 12 were installed opposite to each other in the primarycathodic arc sources of the dual-arc filtered arc source, while theresistance evaporation metal vapor source in a form of DC heatedtungsten foil boat (having alumina coating to reduce chemicalinteraction with evaporating material)) was provided with 100 mg of99.95% pure lanthanum. The substrate was preheated to 400 degrees C.before the deposition stage commenced.

[0194] After ion cleaning as in Example 1, the deflecting magneticsystem 13 of the filtered arc source was activated and a CrN/Al(Si)Nnano-structured multilayer coating was deposited from the dual arcfiltered arc source for a duration of 3 hours to achieve a coatingthickness of about 2 μm. Pure nitrogen as a plasma-creating gas wasinjected into the main chamber 42 to a total operating pressure of4×10⁻⁴ to 6×10⁻⁴ Torr. The substrate bias voltage during deposition ofthe CrN/Al(Si)N coating was held at −60 V, providing extensive ionbombardment of the substrates before the deposition of the main layers.The total current of the auxiliary arc discharge between the chromiumand aluminum cathodes of the filtered arc source and the distalauxiliary anode was set at 100 amps. The rotation speed of the substrateplatform was set at 10 rpm. The nano-structured CrN/CrAl(Si)Nmulti-layer coating consists of CrN interlayers alternating withsuperlattice CrAl(Si)N layers. Each of the CrN interlayers was depositedby evaporating chromium cathode target for 20 seconds while the aluminumtarget was switched off. Each of the CrAl(Si)N superlattice interlayerswas deposited by co-evaporating Cr and Al/6% Si targets for 10 sec. The360 segments of nano-structured multilayer CrN/CrAl(Si)N cermet coating,consisting of CrN interlayers having thickness of about 3 nm followed byCrAl(Si)N interlayers having a thickness of about 2 nm, were depositedto total thickness of about 1.8 μm. At this stage of the process theresistance heating evaporator was activated to evaporate the lanthanum.During evaporation of the lanthanum, the primary cathodic arc sourcewith aluminium target was switched off and nitrogen was changed onoxygen as reactive gas creating a conditions for coinciding depositionof lanthanum chromate upper layer. During this last stage of theprocess, which lasted 2 hrs the highly adhesive lanthanum chromate upperlayer with thickness approximately 1 μm was deposited on a top ofCrN/CrAl(Si)N multilayer superlattice coating. Exposing the strip metalspecimen in the oxidizing atmosphere at 800 deg C. for 10 hrs tested thehot corrosion resistance of the coating. There were no signs ofdegradation of the surface electrical conductivity found after testingcycle.

[0195] Other combinations of alternative first and second layers in asequence of multilayer coating architecture for electrical conductiveand high temperature oxidation resistant coatings for interconnectplates of SOFC is shown in the Table below: Coating First layer (insequence)- Second Layer (in sequence)- composition 10 nm 5 nm CrAlNCrN_(x) CrAl_(x)N_(y) CrAlO CrO_(x) CrAl_(x)O_(y) CrAlSiO CrO_(x)CrAl_(x)Si_(y)O_(z) CrAlSiYO CrO_(x) CrAl_(x)Si_(y)Y_(z)O_(u) CrAlONCrO_(x)N_(y) CrAl_(x)O_(y)N_(z) CrZrO CrO_(x) CrZr_(x)O_(y) CrZrYOCrO_(x) CrZr_(x)Y_(y)O_(z) CrZRAlYO CrO_(x) CrZr_(x)Al_(y)Y_(z)O_(u)

[0196] Preferred embodiments of the invention having been thus describedby way of example, various modifications and adaptations will beapparent to those skilled in the art. The invention is intended toinclude all such modifications and adaptations as fall within the scopeof the appended claims.

I claim:
 1. An apparatus for the application of coatings in a vacuum,comprising at least one filtered arc source comprising at least onecathode contained within a cathode chamber, at least one anodeassociated with the cathode for generating an arc discharge, a plasmaduct in communication with the cathode chamber and with a coatingchamber containing a substrate holder for mounting at least onesubstrate to be coated, the substrate holder being positioned off of anoptical axis of the cathode, at least one deflecting conductor disposedadjacent to the plasma source and the plasma duct, for deflecting aplasma flow from the arc source into the plasma duct, and at least onemetal vapor or sputter deposition plasma source disposed in or near apath of the plasma flow, comprising a material to be evaporated.
 2. Theapparatus of claim 1 wherein the at least one metal vapor plasma sourceis disposed along an optical axis of the substrate holder.
 3. Theapparatus of claim 1 wherein the at least one metal vapor plasma sourceis coupled to the cathode or the anode and disposed off of an opticalaxis of the substrate holder.
 4. The apparatus of claim 3 wherein the atleast one metal vapor plasma source is surrounded by a shield whichinsulates the at least one metal vapor plasma source from the plasmaflow, the shield having an opening to expose material to be evaporatedto the plasma flow.
 5. The apparatus of claim 1 comprising deflectingconductors disposed adjacent to upstream and downstream sides of thecathode, whereby a downstream flow of plasma is generated from the arcsource and deflected toward the plasma duct and an upstream flow ofplasma is generated from the arc source and deflected away from theplasma duct.
 6. The apparatus of claim 5 wherein the evaporator isdisposed between the upstream and downstream plasma flows.
 7. Theapparatus of claim 6 comprising an electron beam for evaporating thematerial.
 8. The apparatus of claim 5 wherein the evaporator is disposedin the upstream plasma flow and the material evaporates under theinfluence of the plasma flow.
 9. The apparatus of claim 1 wherein the atleast one metal vapor plasma source is disposed in a substrate chamberwith the substrate holder.
 10. An apparatus for the application ofcoatings in a vacuum, comprising at least one filtered arc sourcecomprising at least one cathode contained within a cathode chamber, atleast one anode associated with the cathode for generating an arcdischarge, a plasma duct in communication with the cathode chamber andwith a coating chamber containing a substrate holder for mounting atleast one substrate to be coated, the substrate holder being positionedoff of an optical axis of the cathode, at least one deflecting conductordisposed adjacent to the plasma source and the plasma duct, fordeflecting a plasma flow from the arc source into the plasma duct, atleast one metal vapor or sputter deposition plasma source incommunication with the plasma duct, the metal vapor or sputterdeposition plasma source being positioned off of an optical axis of thecathode, and at least one deflecting conductor disposed adjacent to themetal vapor plasma source and the plasma duct, for deflecting a plasmaflow from the metal vapor plasma source into the plasma duct.
 11. Theapparatus of claim 10 wherein the at least one metal vapor plasma sourceis disposed in the coating chamber in opposition to the filtered arcsource.
 12. The apparatus of claim 11 comprising an electron beam forevaporating the material.
 13. The apparatus of claim 10 wherein themetal vapor plasma source comprises a heated evaporated anode surroundedby a shield which insulates the metal vapor plasma source from theplasma flow, the shield having an opening to expose material to beevaporated to the plasma flow.
 14. The apparatus of claim 10 wherein themetal vapor plasma source comprises a heated evaporated cathode.
 15. Theapparatus of claim 10 wherein the metal vapor plasma source comprises aheated evaporated anode.
 16. The apparatus of claim 10 wherein thesputter deposition plasma source comprises a magnetron source.
 17. Theapparatus of claim 10 comprising focusing conductors disposed adjacentto the metal vapor plasma source and the plasma duct on upstream anddownstream sides of the metal vapor plasma source, for focusing a plasmaflow from the metal vapor plasma source to the plasma duct.
 18. Theapparatus of claim 17, wherein the metal vapor plasma source is disposedin a plane of symmetry between magnetic cusps of the focusingconductors.
 19. The apparatus of claim 10 wherein impulse lasers arepositioned to ignite an impulse vacuum arc discharge on a surface of thecathode.
 20. The apparatus of claim 19 comprising a grounded deflectinganode and a repelling anode for directing an ion plasma stream towardthe at least one substrate.
 21. The apparatus of claim 20 wherein thecathode comprises a non-conductive evaporating material and a powersupply is installed between the repelling anode and ground.
 21. A methodof coating an article in a coating apparatus comprising at least onefiltered arc source comprising at least one cathode contained within acathode chamber, at least one anode associated with the cathode forgenerating an arc discharge, a plasma duct in communication with thecathode chamber and with a coating chamber containing a substrate holderfor mounting at least one substrate to be coated, the substrate holderbeing positioned off of an optical axis of the cathode, at least onedeflecting conductor disposed adjacent to the plasma source and theplasma duct, for deflecting a plasma flow from the arc source into theplasma duct, and at least one metal vapor or sputter deposition plasmasource in communication with the plasma duct, the method comprising thesteps of: a. generating an arc between the cathodic arc source and theanode to create a plasma of cathodic evaporate, b. evaporating orsputtering a material in the metal vapor plasma source or sputterdeposition plasma source to generate a metal vapor or sputter flux inthe vicinity of the plasma flow, and c. deflecting a flow of the plasmatoward the substrate holder,  whereby the flow of plasma mixes with themetal vapor or sputter flux prior to coating the at least one substrate.22. The method of claim 21 wherein the metal vapor plasma source orsputter deposition plasma source is disposed in or near the flow ofplasma.
 23. The method of claim 21 wherein the metal vapor plasma sourceor sputter deposition plasma source is disposed remote from the flow ofplasma and including after step b. the step of deflecting the metalvapor into the plasma duct.
 24. The method of claim 23 wherein the metalvapor plasma source or sputter deposition plasma source is disposed offof an optical axis of the substrate holder.
 25. The method of claim 24including after step b. the step of focusing the metal vapor plasma orsputter plasma prior to deflecting the metal vapor plasma or sputterplasma into the plasma duct.